The Calendar hole will go live in approximately 11 days. Why not try and solve it ahead of time?
Collatz in all languages in bytes. Achievements Cheevos Holes Languages Medals Miscellaneous All Holes 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig 05AB1E ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig Experimental Language 05AB1E ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Hole All 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Experimental Hole Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Bytes Time Submitted 599th Just4FunCoder 883 70 20ms 17 Feb 2024 599th ThijsLuttikhuis 883 70 19ms 3 Mar 2024 599th elgan65536 883 70 19ms 5 Mar 2024 599th jtaxen 883 70 18ms 1 Apr 2024 599th HumanoidCPU 883 70 19ms 6 May 2024 599th abc7-12 883 70 18ms 6 May 2024 599th ahmetdemirag 🇨🇾 883 70 18ms 9 Jun 2024 599th FranklinJiaChen 883 70 21ms 4 Jul 2024 599th 5cw 🇺🇸 883 70 18ms 13 Jul 2024 599th CaedenHarper 🇨🇦 883 70 18ms 3 Aug 2024 599th emgordon154 883 70 19ms 5 Aug 2024 599th dokutan 883 70 23ms 9 Aug 2024 599th jatloe 883 70 19ms 26 Aug 2024 599th lgrandco 883 70 19ms 9 Oct 2024 599th snydej 883 70 19ms 21 Nov 2024 599th erikji 883 70 19ms 4 Feb 2025 599th CutSandstone 883 70 19ms 4 Feb 2025 599th albanian-laundromat 883 70 19ms 12 Apr 2025 599th xsot 🇸🇬 883 70 22ms 3 May 2025 599th fuzzylojik-golf 🇺🇸 883 70 19ms 14 Jun 2025 599th smilesformiles3 883 70 19ms 14 Jun 2025 599th KasperKivimaeki 🇫🇮 883 70 19ms 30 Jun 2025 599th adaGrad1 883 70 18ms 10 Aug 2025 599th EthanJantz 883 70 18ms 10 Aug 2025 599th qpwoeirut 883 70 16ms 10 Aug 2025 599th katss2 883 70 19ms 17 Aug 2025 599th intgrah 883 70 18ms 23 Sep 2025 599th ryyyn 🇺🇸 883 70 18ms 29 Oct 2025 599th luuumine 🇫🇷 883 70 18ms 3 Nov 2025 599th Babafaba 883 70 19ms 7 Nov 2025 599th commandblockguy 🇺🇸 883 70 19ms 16 Nov 2025 599th hellopir2 883 70 22ms 27 days ago 599th bzijlema 🇳🇱 883 70 20ms 17 days ago 674th Irratix 🇳🇱 883 96 57ms 4 May 2022 674th MeWhenI 🇻🇦 883 96 83ms 1 Jun 2022 674th janbehrens 🇩🇪 883 96 57ms 21 Apr 2023 674th Shanethegamer 🇺🇸 883 96 69ms 15 May 2023 674th Yewzir 🇧🇪 883 96 81ms 11 Nov 2023 674th MateuszPietrzak 🇵🇱 883 96 61ms 18 Nov 2023 674th kkoenig 883 96 59ms 21 Dec 2023 674th BlankSpruce 883 96 85ms 20 Aug 2024 674th fuzzylojik-golf 🇺🇸 883 96 86ms 14 Jun 2025 683rd Shanethegamer 🇺🇸 882 51 428ms 15 May 2023 684th GrayJoKing 🇦🇺 882 60 133ms 24 Oct 2024 685th GrayJoKing 🇦🇺 882 84 37ms 19 Jun 2022 685th primo-ppcg 🇹🇭 882 84 36ms 29 Jun 2022 687th Shanethegamer 🇺🇸 881 73 90ms 8 May 2025 687th DialFrost 🇸🇬 881 73 83ms 3 Jun 2025 687th edsrzf 🇳🇿 881 73 98ms 4 Jul 2025 690th Shanethegamer 🇺🇸 881 142 511ms 27 Mar 2025 690th DialFrost 🇸🇬 881 142 490ms 28 Mar 2025 690th emgordon154 881 142 395ms 10 Apr 2025 690th GolfingSuccess 🇬🇷 881 142 463ms 14 days ago 694th primo-ppcg 🇹🇭 881 193 107ms 14 Aug 2025 695th dokutan 880 62 5ms 28 Apr 2025 696th johnnythedoggie 880 72 91ms 13 May 2022 696th kaascevich 880 72 90ms 8 Jul 2025 698th Grrisly 880 74 4ms 25 Mar 2024 699th Shanethegamer 🇺🇸 878 66 172ms 4 May 2022 699th scpchicken 🇵🇼 878 66 254ms 5 May 2022 699th sisyphus-ppcg 🇦🇺 878 66 174ms 6 May 2022 699th Natanaelel 🇸🇪 878 66 144ms 15 Jun 2022 699th Z-snails 878 66 254ms 27 Feb 2023 699th Jeremy-Stafford 878 66 258ms 27 Feb 2023 699th alomiF 878 66 293ms 1 Sep 2023 699th btnlq 878 66 145ms 17 Oct 2023 707th DialFrost 🇸🇬 878 86 40ms 24 Oct 2024 707th stefangimmillaro 878 86 42ms 14 Jan 2025 709th emgordon154 878 97 128ms 16 days ago 710th JayXon 🇺🇸 878 158 1,772ms 14 Sep 2025 711th c0d3-4-F00d 🇩🇪 877 61 10ms 6 May 2022 711th jackkav 877 61 10ms 26 Jun 2022 711th TechNolaByte 877 61 10ms 6 Jul 2022 711th Heathcorp 🇦🇺 877 61 9ms 17 Jul 2022 711th C0de5mith 🇺🇸 877 61 11ms 3 Aug 2022 711th sebipopa 🇷🇴 877 61 10ms 18 Aug 2022 711th moikaturns 🇬🇧 877 61 9ms 25 Sep 2022 711th FlorianCassayre 🇫🇷 877 61 10ms 27 Sep 2022 711th Mazn3k 877 61 10ms 1 Feb 2023 711th tvcv901 877 61 10ms 22 Mar 2023 First Prev 641–720 of 3,529 Next Last