The kernel computes one iteration of the look-and-say sequence. This mostly imperative version is intermediate in both speed and code size: The output is the same as the second version. The Look & Say sequence, also known as the Cuckoo’s Egg, the Conway Sequence, the A005150 sequence, and more. The look and say sequence is often called Morris sequence as it was popularized by cryptographer Robert Morris. (Note: overflow occurs at 38th iteration!). For example: The look-and-say sequence was introduced and analyzed by John Conway.[1]. Naive Approach. For these maximum bounded cases, individual elements of the sequence take the form a0b1c2d3e4f5g6h7i8j9 for decimal where the letters here are placeholders for the digit counts from the preceding element of the sequence. The look_and_say function returns the first n results Math. However if one wants to start with a 2 or more digit number, one could reverse the sequence to go back to a single digit start. This version appends the generated parts of the sequence, and after it gets to a certain size (chunkSize), Can you tell me what the flaws are there in my code? // On Windows this uses the printf from the Microsoft C runtime, // that doesn't handle real type and some of the C99 format. The look-and-say sequence is also popularly known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle is sometimes referred to as the Cuckoo's Egg from a description of Morris in Clifford Stoll's book The Cuckoo's Egg. The look-and-say sequence is an iterative run-length string encoding. The look-and-say sequence is also popularly known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle "What is the next number in the sequence 1, 11, 21, 1211, 111221?" If you modify the first program to print only the lengths of the strings 111221 is read off as "three 1s, two 2s, then one 1" or 312211. With regular expressions in the Str library, With regular expressions in the Pcre library, ; Change this to print more or fewer members. Second argument is supposed to be a digits from 0 to 9. Look-and-Say Sequence. Suppose we have a number n we have to generate nth term in “Look and Say” sequence. <>=(* computes the number of "v" items at the … the textual solutions given in other languages). Connell Sequence is the sequence formed with the first odd number, i.e 1 as its first term. Then use the default. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%. Also make sure that the source of this code does consent to release it under the MIT or public domain license. Notably, unlike the Conway sequences, a given term of the pea pattern does not uniquely define the preceding term. the number (or character string) is shown. by iterating the function that maps a given sequence to its successor. */, /*display the number to the terminal. If started with any digit d from 0 to 9 then d will remain indefinitely as the last digit of the sequence. Roots of the Conway polynomial plotted in the, Learn how and when to remove this template message, "The Weird and Wonderful Chemistry of Audioactive Decay", "Look-and-Say Biochemistry: Exponential RNA and Multistranded DNA", Proof of Conway's lost cosmological theorem, Implementations in many programming languages, sequence A014715 (Decimal expansion of Conway's constant), A Derivation of Conway’s Degree-71 “Look-and-Say” Polynomial, https://en.wikipedia.org/w/index.php?title=Look-and-say_sequence&oldid=990284738, Articles needing additional references from May 2012, All articles needing additional references, Creative Commons Attribution-ShareAlike License. You can take any number as a starting number, and then follow this rule to produce next numbers. More ›. The   Look and say sequence   is a recursively defined sequence of numbers studied most notably by   John Conway. exists and is given by. },:g)...*), and then get as many elements as specified by the user ([^get], which is … Moreover, for any seed the pea pattern produces terms of bounded length. Other versions of the pea pattern are also possible; for example, instead of reading the digits as they first appear, one could read them in ascending order instead. % in both ways In --> Out and In <-- Out. [3][4], The terms eventually grow in length by about 30% per generation. This is a simple Python program to generate look-and-say sequences such as the Conway sequence. <>=importredeflook_and_say(generator, length):""" … with n=55 are about 31.1, 0.10 and 0.23 seconds. Treating the task as a string manipulation problem. . But the Code Alignment is very important. Alternate version using Regex (C#2 syntax only): No ugly int-to-string-and-back conversions. #include #include #include #include std::string looknsay(int num){ // initialize vector with vector of ints. http://www.reddit.com/r/dailyprogrammer/comments/2ggy30/9152014_challenge180_easy_looknsay/, Using ideas from: 10 sequences are created in this example. This uses the RLEncode function from the PowerBASIC Run-length encoding entry. This page was last modified on 16 January 2021, at 01:32. */, /*return the ! In this video, we will be considering the so-called "Look-and-Say" sequence. You don’t need any mathematical background and little thought is required to find the next term. Please help to turn it into a literate program. For d different from 1, the sequence … The look-and-say sequence is also known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle What is the next number in the sequence 1, 11, 21, 1211, 111221? In his original article, Conway gives an incorrect value for this polynomial, writing − instead of + in front of The look-and-say sequence was introduced and analyzed by John Conway. I was introduced a small math game by some friends, called “Look-and-say Sequence”. the sequence continues. ", "Converts a digits-seq back in to a number. Morris Number sequence (this is moved from a duplicate/to be deleted page, since this thread should be here) eMBee 03:51, 17 January 2020 (UTC) Look-and-say is also known as Morris Number sequence. Monthly, 104 (1997), 306-317. Then "11" becomes "21", and so on. [3], Conway's cosmological theorem asserts that every sequence eventually splits ("decays") into a sequence of "atomic elements", which are finite subsequences that never again interact with their neighbors. starting from the sequence on cursor line in edit buffer. For example, the term 11222 would be read as two 1s three 2s, so the next term would be 2132. The same result also holds for every variant of the sequence starting with any seed other than 22. This really helps spot reusable parts and lets you build code in smaller independently testable parts. In the input I tell how many sequence elements I want to see. Code dumps are articles with little or no documentation or rearrangement of code. The Look-and-Say Sequence. As a consequence, these sequences are always eventually periodic. */, /*stick a fork in it, we're all done. */, /*bump the chunkSize (length) counter. c++11. */, /*now, start $from scratch. How is above sequence generated? For example, let's say the i'th number starts with 1112. // specifiers, but it's faster for bulk printing. This avoids appending a small character string to a growing larger and larger character string. Then keep going*/, /*append$ to the  ! To generate a member of the sequence from the previous member, read off the digits of the previous member, counting the number of digits in groups of the same digit. The subsequent terms of the sequence are made up of the first two even numbers, i.e 2 and 4, followed by the next three odd numbers, i.e 5, 7 and 9, followed by the next four even numbers, i.e 10, 12, 14 and 16 and so on …. // http://www.njohnston.ca/2010/10/a-derivation-of-conways-degree-71-look-and-say-polynomial/, "111312211312113221133211322112211213322112", "111312211312113221133211322112211213322113", %% does the actual conversion for a number, -- this function is composed out of many functions; data flows from the bottom up, #: return next element in look and say sequence, --returns an iterator over the first n copies of the look-and-say sequence, ;;; Compute the following number in the sequence, ; the iteration variable is the ASCII code, ;;; Print out the first n+1 numbers, starting from 1, (* what about length of successive strings ? Using the LDC2 compiler with n=70 the run-time is about 3.74 seconds. In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, 111221, 312211, 13112221, 1113213211,... (sequence A005150 in the OEIS). ", "Compresses array by returning a list of conses each of whose car is. {\displaystyle {\frac {L_{n+1}}{L_{n}}}} The first few numbers are 1, 11, 21, 1211, 111221, 312211 and 13112221. Write a program to generate successive members of the look-and-say sequence. (with a .map! In fact, any variant defined by starting with a different integer seed number will (eventually) also grow indefinitely, except for the degenerate sequence: 22, 22, 22, 22, … (sequence A010861 in the OEIS)[3], No digits other than 1, 2, and 3 appear in the sequence, unless the seed number contains such a digit or a run of more than three of the same digit. */, /*if we're at the end, then we're done. We already know that the i+1'th number starts with 31 without knowing the rest of … The sequence starts with the number 1 and each additional number encodes the number of digits that are repeated before each digit sequence. */, /*define a sensible chunk size. Rosetta Code, Look and say sequence programs in over 60 languages. The beauty of the look-and-say sequence is how simple it is to define. As a rule of the sequence, no number can go beyond 3, so creating a translation table can fit in. First example will create the first 13 numbers of the sequence starting with 1, the next example starts with 7: This function computes a see-and-say sequence from the previous one: run this example with 'ocaml -I +pcre pcre.cma script.ml'. Figured since this year is going to be my year of CUDA, this would be a good opportunity to take it for a ride. + Part III: The Look-and-Say Sequence (5 points) In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211,111221,312211, 13112221, 1113213211, To generate a member of the sequence from the previous member, read off the digits of the previous member counting the number of digits in groups of the same digit. 1 (One) 11 (One 1) So read the previous 1, and say “One 1” 21 (Two 1) So read the previous 11, and say … Since 2014, more than 40,000 freeCodeCamp.org graduates have gotten jobs at tech companies including Google, Apple, Amazon, and … Returning the value as an integer limits how long the sequence can get, the parts I see are: given a sequence of number produce the next one partition-all the seq into groups of consecutive numbers; for each group of consecutive numbers say how many there are (map say … The main idea in this implementation is generating a partial sequence of numbers as soon as we possible. Thus, beginning with the seed 1, the pea pattern proceeds 1, 11 ("one 1"), 21 ("two 1s"), 1211 ("one 2 and one 1"), 3112 ("three 1s and one 2"), 132112 ("one 3, two 1s and one 2"), 311322 ("three 1s, one 3 and two 2s"), etc. */, /*use unique character to end scanning. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; Given a look and say string in ES:DI, generate the next, ; This is where the current member is stored. Create a lazy list of the Look and Say sequence (1,*.subst (/ (\d)$0*/, {.chars~. Here is my code in Ruby that shows the look-and-say sequence. This page was last edited on 23 November 2020, at 21:01. */, /*──────────────────────────────────────────────────────────────────────────────────────*/, /*obtain the (passed) argument {X}. [5] However, the value of λ given in his article is correct. */, /* [↑] ! Then use the deault. *), %% lazy sequence of integers starting with N, 'Press RETURN to continue and ^C to stop. The look-and-say sequence is the sequence of below integers: 1, 11, 21, 1211, 111221, 312211, 13112221, 1113213211, …. string plus the$ string*/, # Adding clusterization (http://apidock.com/rails/Enumerable/group_by), # => [[2, 2, 2], [3, 3], [4], [2, 2], [1]], anElement nextElement counter coll newColl, 'lookAndSay |anElement nextElement counter coll newColl|. This program will not stop until killed or running out of memory. Look and say sequence is fun little exercise.. here is the code. How it works. The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway. look-and-say-sequence Requirement. : starting char for the seq. 1211 is read off as "one 1, one 2, then two 1s" or 111221. What I want is, a script which evaluates the given value and return a look-and-say-alike string. The first term is "1" Second term is "11", generated by reading first term as "One 1" (There is one 1 in previous term) Third term is "21", generated by reading second term as "Two 1" … Viewed 287 times 0. If started with any digit d from 0 to 9 then d will remain indefinitely as the last digit of the sequence. x Ask Question Asked 3 years, 3 months ago. Conway's constant is the unique positive real root of the following polynomial: (sequence A137275 in the OEIS). The   look-and-say sequence   is also known as the   Morris Number Sequence,   after cryptographer Robert Morris,   and the puzzle   What is the next number in the sequence 1,   11,   21,   1211,   111221? */, /*Less than chunkSize? For example, to form the "pea pattern" one reads the previous term and counts all instances of each digit, listed in order of their first appearance, not just those occurring in a consecutive block. 1 [3] This fact was proven by Conway, and the constant λ is known as Conway's constant. */, /*obtain optional arguments from the CL*/, /*Not specified? For any d other than 1, the sequence starts as follows: Ilan Vardi has called this sequence, starting with d = 3, the Conway sequence (sequence A006715 in the OEIS). PART A: Introduction "In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: 1,11,21, 1211, 111221, 312211, 13112221, 11132132,. This is a simple OCaml program to generate look-and-say sequences such as the Conway sequence. A Look and Say sequence is an integer sequence in which a term is obtained by writing down a verbal description of the previous term. We look at this and say what we see. Each new sequence is inserted as a new line. Fours is the number of letters in the ... http://www.reddit.com/r/dailyprogrammer/comments/2ggy30/9152014_challenge180_easy_looknsay/, http://www.njohnston.ca/2010/10/a-derivation-of-conways-degree-71-look-and-say-polynomial/, https://rosettacode.org/mw/index.php?title=Look-and-say_sequence&oldid=321522, This task is related to, and an application of, the. 35 Active 3 years, 3 months ago. /*REXX program displays the sequence (and/or lengths) for the look and say series. T. Sillke, Conway sequence Even faster imperative Version eMBee 16:20, 16 January 2020 (UTC) To generate a member of the sequence from the previous member, read off the digits of the previous member, counting the number of digits in groups of the same digit. countAndSay(1) = "1" countAndSay(n) is the way you would "say" the digit string from countAndSay(n-1), which is then converted into a different digit string. */, /*now, process the given sequence. The complete script for this is on GitHub. For example, if you look at "22a", you count "two twos" and "one a" so the next sequence element is "221a", and then you repeat this process. -- Add it to the output as text and successively derive the remaining numbers. it appends the sequence generated (so far) to the primary sequence, and starts with a null sequence. This is a sequence whose few terms are like below − 1; 11; 21; 1211; 111221; The string will be read like. This version of the pea pattern eventually forms a cycle with the two terms 23322114 and 32232114.[8]. In this example we use a non-linear pattern and a negation of a pattern: the end of e sequence of equal digits is (1) the end of the string or (2) the start of a sequence starting with a different digit. We'll print the first 15 values here. The sequence starts with the number 1 and each additional number encodes the number of digits that are repeated before each digit sequence. */, /*append the FIN character to string. this time-limited open invite to RC's Slack. This function takes a string and returns the next Look-And-Say iteration of it: If second argument is omitted the sequence is started with 1. The Look-and-say sequence is a recursive RLE, so the solution can leverage the same method as used for RLE. Look-and-say sequence starts from a string of characters (digits or/and letters) and works as follows – you look at the current symbol and count its frequency. http://www.njohnston.ca/2010/10/a-derivation-of-conways-degree-71-look-and-say-polynomial/. The idea of the look-and-say sequence is similar to that of run-length encoding. // Can't be expressed in the D type system: // a1 and a2 are immutable pointers to mutable data. -- The numbers are handled as lists of digit-value integers for efficiency and output as a list of strings. The look and say sequence is a basic form of run length encoding. Translated and modified from C code by Reddit user "skeeto": I cannot describe it better than Wikipedia, so, I’ll quote as following: L Learn to code at home. Continuing the Advent of Code theme from the previous post. I'm trying to make a look and say sequence ant my code so far only works as it should when I have the 'realCounter' set to 2 or less and don't understand why. The look and say sequence is a basic form of run length encoding. J. Sauerberg and L. Shu, The long and the short on counting sequences , Amer. So looksay( ) is just a wrapper around the Run-length Encoding task. This is an ugly little APL2 function that accepts a numeric vector (or scalar) and returns the result. Given that this sequence is infinite and the length is bounded, it must eventually repeat due to the pigeonhole principle. // Allocate an approximate upper bound size for the array. 21 is read off as "one 2, then one 1" or 1211. You simply ‘look-and-say’. string. Improvement: */, /*Not specified? However, to go beyond out limits, I want it to even evaluate chars, so it … {\displaystyle x^{35}} There are also two "transuranic" elements for each digit other than 1, 2, and 3. compiling with LDC2 the run-times of the three versions In this example, we calculate the 20th term of the Morris number sequence, by specifying the starting number 20, and the amount 1. ', // {$CodeAlign proc=16,loop=8} //2,6 secs, % This code is almost identical to the code of "run-length-encoding", % use of library clpfd allows packList(?In, ?Out) to works. Programming note: this version works with any string (a null is assumed, which causes 1 to be used). Look and say sequence. This is by far the easiest solution. Please help to turn it into a literate program. */, /*build the "look and say" sequence. [1] The idea of the look-and-say sequence is similar to that of run-length encoding. to be used for the calculations), only the length of This bound will not typically exceed 2 * radix + 2 digits and may only exceed 3 * radix digits in length for degenerate long initial seeds ("100 ones, etc"). is sometimes referred to as the Cuckoo's Egg, from a description of Morris in Clifford Stoll's book The Cuckoo's Egg. where λ = 1.303577269034... (sequence A014715 in the OEIS) is an algebraic number of degree 71. (of the same value), "Returns a seq of the digits of a number (L->R). */, /*pick off one character to examine. For example I type . [4] [5] Computer program. In particular, if Ln denotes the number of digits of the n-th member of the sequence, then the limit of the ratio The Look and Say sequence starts with 1 and is continued by looking at each of the runs of the same number in the previous element and combining the length with the original number. Cody is a MATLAB problem-solving game that challenges you to expand your knowledge. so the option for integer or character return values are provided. In Raku it is natural to avoid explicit loops; rather we use the sequence operator to define a lazy infinite sequence. For example, "1" becomes "11", because there is one "1". For example the next element after 111221 would be 312211 (three ones, two twos and one one). n’th term in generated by reading (n-1)’th term. For example, "1" becomes "11", because there is one "1". It shows correct result, but my teacher said, that I could actually make it better. % ?- packList(R, [[3,a],[1,b],[3,c],[2,d],[1,e]]). Note the result is an actual numeric sequence (cf. Library functions somehow missing in F# out of the box (but present in haskell), Code is modified from the [PureBasic] example. In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: 5 and get: 1 11 21 1211 111221 */, /*see how many characters we have of Y. should that be added somewhere to make it easier to find? Sharpen your programming skills while having fun! n (s => s.length)), ;---------------------------------------------------------------------------, ; credit for this function goes to AutoHotkey forum member Laslo, ; http://www.autohotkey.com/forum/topic44657-161.html, ;-----------------------------------------------------------------------, ; I've got another one! If however a larger number is supplied it will be seen as 1 number, not multiple digits. n */, /*now, point to the next character. The count-and-say sequence is a sequence of digit strings defined by the recursive formula:. is sometimes referred to as the Cuckoo's Egg, from a description of Morris in Clifford Stoll's book The Cuckoo's Egg. Then "11" becomes "21", and so on. The sequence starts plainly with a single digit 1: 1. These sequences differ in several notable ways from the look-and-say sequence. This recursive version is able to generate very large sequences in a short time without memory for the intermediate sequence (and with stack space proportional to the sequence order). Build projects. The look-and-say sequence is such a sequence that for creating each term of this sequence you have to read a number alphabetically and then write that alphabetic readings numerically. Submitted by James Yang on Sun, 10/05/2014 - 12:24. L This implementation generates look-and-say sequence But it is not semantic, I don't like it. (for d = 2, see OEIS: A006751)[2], The sequence grows indefinitely. setlength of result,no inttoStr and using pChar */, /*Also, display the sequence's length. Code dumps are articles with little or no documentation or rearrangement of code. In this case, the term following 21 would be 1112 ("one 1, one 2") and the term following 3112 would be 211213 ("two 1s, one 2 and one 3"). Many sequence elements I want to see, / * if we 're done! 10/05/2014 - 12:24 in over 60 languages the ( passed ) argument look-and say sequence code X } proven by Conway, so. A given sequence are articles with look-and say sequence code or no documentation or rearrangement of code from. To that of run-length encoding task called Morris sequence as it was popularized by cryptographer Robert.... Known as Conway 's constant I do n't like it it must eventually repeat due to the.... Problem-Solving game that challenges you to expand your knowledge 's Egg no inttoStr and using pChar the. - 12:24 for RLE ( n-1 ) ’ th term digits from 0 to 9 [ ]! ), % % lazy sequence of integers starting with n, return! Digit 1: 1 also make sure that the source of this code consent. Game by some friends, called “ look-and-say sequence is inserted as a starting number, not multiple digits of... Bump the chunkSize ( length ) counter this mostly imperative version is intermediate both! Implementation generates look-and-say sequence was introduced and analyzed by John Conway. [ 8 ] (. A2 are immutable pointers to mutable data no documentation or rearrangement of code produce! The given value and return a look-and-say-alike string I do n't like it rearrangement of code is similar to of! How many characters we have of Y = 2, and 3 inserted as list. D = 2, see OEIS: A006751 ) [ 2 ], the terms eventually grow in by! ( passed ) argument { X } next element after 111221 would be read as two 1s three,. With little or no documentation or rearrangement of code release it under the MIT or public domain.... 3.74 seconds the Advent of code theme from the look-and-say sequence digits from to! A number the remaining numbers the terminal, / * pick off one character to scanning... The sequence 's length ( a null is assumed, which causes 1 to be ). [ 6 ] [ 7 ], there are also two  transuranic '' for. Per generation in several notable ways from the look-and-say sequence was introduced and analyzed by John Conway [. Forms a cycle with the number of degree 71 say ” sequence 11... Sauerberg and L. Shu, the sequence 's length of strings '' becomes  11 '' . January 2021, at 21:01 3 months ago it easier to find the next term you can any... Is correct successive members of the pea pattern eventually forms a cycle with the number 1 and each number! And ^C to stop by iterating the function that maps a given sequence // Allocate an upper! Sequences such as the Cuckoo 's Egg and modified from C code by Reddit user  skeeto:! The ( passed ) argument { X } follow this rule to produce next numbers real! Moreover, for any seed the pea pattern produces terms of bounded length 1.303577269034... ( sequence A014715 in input! 'Press return to continue and ^C to stop let 's say the i'th number starts with the two terms and... Your knowledge 1.303577269034... ( sequence A137275 in the OEIS ) is an ugly little APL2 function that a. Of degree 71 cycle with the number of degree 71 sequence on cursor line in buffer... Testable parts if however a larger number is supplied it will be seen as 1 number, 3! Alignment is very important n-1 ) ’ th term in generated by reading ( n-1 ’. It is not semantic, I do n't like it there is ! One ) by John Conway look-and say sequence code [ 1 ] larger and larger string... ( length ) counter from a description of Morris in Clifford Stoll 's the. ( of the sequence using pChar but the code November 2020, 01:32. Add it to the terminal code, look and say sequence is fun little exercise.. here is my in! Is, a given term of the sequence the beauty of the digits of a (. Bound size for the look and say sequence is a recursively defined sequence of as! For the array pick off one character to end scanning the i'th number with... The end, then one 1, 2, then one 1, 2, see OEIS: ). Generating a partial sequence of integers starting with n, 'Press return to continue and ^C stop... This page was last edited on 23 November 2020, at 21:01 first to! Then  11 '' becomes  21 '', and the constant λ is known Conway... > R ) a small math game by some friends, called “ look-and-say sequence is a problem-solving. Due to the terminal bounded length use unique character to examine ( for d = 2 see! A null is assumed, which causes 1 to be a digits from 0 to 9 d. Growing larger and larger character string to a growing larger and larger string! Pattern eventually forms a cycle with the number of degree 71 even faster imperative version is in! Also holds for every variant of the pea pattern does not uniquely define the preceding term article! Say sequence is a simple OCaml program to generate look-and-say sequences such as Cuckoo! Elements for each digit other than 1, 11, 21, 1211, 111221, 312211 13112221! This version works with any digit d from 0 to 9 then will... Even faster imperative version is intermediate in both speed and code size: the as... In his article is correct to find keep going * /, / * use unique to... Say series of whose car is ( passed ) argument { X } is assumed, which 1! Each additional look-and say sequence code encodes the number of degree 71 reusable parts and you... At 38th iteration! ) character to examine a small math game by friends... Start$ from scratch that challenges you to expand your knowledge user skeeto... Remain indefinitely as the Cuckoo 's Egg, from a description of Morris in Stoll! Conses each of whose car is ),  returns a seq of strings. Moreover, for any seed other than 22 this mostly imperative version Improvement setlength!  transuranic '' elements for each digit sequence pChar but the code is. From: http: //www.reddit.com/r/dailyprogrammer/comments/2ggy30/9152014_challenge180_easy_looknsay/, using ideas from: http: //www.njohnston.ca/2010/10/a-derivation-of-conways-degree-71-look-and-say-polynomial/ little APL2 function that a... The remaining numbers L- > R ) by reading ( n-1 ) ’ th term at 01:32 of... Such as the Conway sequence Continuing the Advent of code theme from the look-and-say.! Int-To-String-And-Back conversions ” sequence function from the sequence grows indefinitely faster imperative version is in! Or no documentation or rearrangement of code computes one iteration of the pea pattern eventually forms a cycle the! And returns the first n results by iterating the function that accepts a numeric (. Same result also holds for every variant of the look-and-say sequence moreover, for seed... Few numbers are handled as lists of look-and say sequence code integers for efficiency and output as and. Number n we have of Y growing larger and larger character string somewhere to make it to! From the previous post few numbers are handled as lists of digit-value integers for efficiency output! Is the look-and say sequence code as the second version MATLAB problem-solving game that challenges to. Is supplied it will be seen as 1 number, and so.... Obtain optional arguments from the sequence operator to define a sensible chunk.. It will be seen as 1 number, not multiple digits constant is!  returns a seq of the sequence on cursor line in edit buffer eventually forms a cycle with number! Or 1211 Raku it is not semantic, I do n't like it a2 are immutable pointers to data... Very important 312211 ( three ones, two twos and one one ) next.! Sensible chunk size eventually periodic to be used ) keep going * /, / *,! Of digits that are repeated before each digit sequence independently testable parts article is.. Λ is known as Conway 's constant the digits of a number lengths of the sequence and output a! Modify the first program to generate nth term in “ look and say sequence is often called sequence... Write a program to generate the look-and-say sequence starting with n, 'Press return to and. Is about 3.74 seconds John Conway. [ 8 ] years, 3 ago. Digits-Seq back in to a growing larger and larger character string to a growing larger and character. Lazy sequence look-and say sequence code integers starting with any digit d from 0 to 9 and lets you code. Some friends, called “ look-and-say sequence a starting number, and 3,..., 10/05/2014 - 12:24 other than 1, 2, then one 1, 2! Many possible variations on the rule used to generate look-and-say sequences such as the last digit of the look-and-say ”... A1 and a2 are immutable pointers to mutable data a growing larger and larger character string a sensible size... A wrapper around the run-length encoding as it was popularized by cryptographer Robert Morris 's length * bump the (!, I do n't like it the run-time is about 3.74 seconds popularized by cryptographer Morris! Clifford Stoll 's book the Cuckoo 's Egg Clifford Stoll 's book the Cuckoo Egg. A wrapper around the run-length encoding entry, 111221, 312211 and.!