The Calendar hole will go live in approximately 13 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 560th MeWhenI 🇻🇦 888 85 41ms 21 Apr 2025 562nd Shanethegamer 🇺🇸 887 70 99ms 12 Dec 2022 562nd Alessandro-Balconi 🇮🇹 887 70 95ms 26 Dec 2022 564th ovs-code 🇩🇪 887 73 340ms 22 Jul 2023 565th albanian-laundromat 887 94 415ms 24 Sep 2025 565th jkelly467 887 94 544ms 23 Oct 2025 565th HumanoidCPU 887 94 397ms 8 Nov 2025 568th snoozingnewt 🇨🇦 887 96 109ms 14 days ago 569th GolfingSuccess 🇬🇷 886 71 2ms 5 May 2022 569th emplv 🇱🇻 886 71 2ms 5 May 2022 569th JayXon 🇺🇸 886 71 2ms 7 May 2022 569th nwellnhof 🇩🇪 886 71 2ms 5 Jun 2022 569th stefangimmillaro 886 71 2ms 2 Jun 2023 569th 09cf 886 71 7ms 4 Oct 2023 569th kkoenig 886 71 2ms 21 Dec 2023 569th sean-niemann 🇺🇸 886 71 2ms 10 Jul 2024 569th masinag 🇮🇹 886 71 2ms 6 Oct 2024 578th janbehrens 🇩🇪 886 90 442ms 21 Apr 2023 578th Yewzir 🇧🇪 886 90 426ms 22 Apr 2023 578th DialFrost 🇸🇬 886 90 440ms 6 Nov 2023 578th Ripick 886 90 439ms 27 Nov 2024 578th emgordon154 886 90 368ms 8 days ago 583rd m-tkach 🇺🇦 886 112 118ms 22 Jun 2025 584th steffan-polygolf 885 74 136ms 14 Feb 2024 585th SiestaGuru 885 88 326ms 9 Jan 2023 585th rifatx 885 88 322ms 5 Jul 2024 585th kmathis22 885 88 367ms 25 Sep 2025 585th arcpolaris 885 88 391ms 8 Nov 2025 589th m-tkach 🇺🇦 884 59 404ms 21 Jan 2024 589th GolfingSuccess 🇬🇷 884 59 474ms 20 Jan 2025 589th duckyluuk 🇳🇱 884 59 450ms 13 days ago 592nd kg583 🇺🇸 884 84 18ms 30 Jul 2025 593rd nipzu 884 94 116ms 17 May 2022 593rd Natanaelel 🇸🇪 884 94 125ms 17 Jun 2022 593rd nkoppel 884 94 120ms 19 Oct 2022 593rd ovs-code 🇩🇪 884 94 120ms 21 Jun 2023 593rd mousetail 🇳🇱 884 94 124ms 12 Jan 2024 598th sean-niemann 🇺🇸 884 109 274ms 25 May 2024 598th GolfingSuccess 🇬🇷 884 109 273ms 6 Sep 2025 600th MichalMarsalek 🇨🇿 883 70 19ms 5 May 2022 600th primo-ppcg 🇹🇭 883 70 23ms 5 May 2022 600th SirBogman 🇺🇸 883 70 19ms 5 May 2022 600th prplz 🇦🇺 883 70 18ms 5 May 2022 600th Irratix 🇳🇱 883 70 18ms 7 May 2022 600th rak1507 🇬🇧 883 70 19ms 7 May 2022 600th inventshah 883 70 17ms 9 May 2022 600th k3w1k0d3r 883 70 18ms 22 Jun 2022 600th ZakkkkAttackkkk 🇵🇭 883 70 17ms 14 Jul 2022 600th Bonjour27891 🇻🇳 883 70 20ms 14 Jul 2022 600th OllieBoyne 🇬🇧 883 70 18ms 19 Jul 2022 600th wen1now 883 70 19ms 8 Aug 2022 600th 051 🇸🇬 883 70 18ms 8 Aug 2022 600th Sp3000 🇦🇺 883 70 19ms 8 Aug 2022 600th betaveros 883 70 19ms 9 Aug 2022 600th shelerr 883 70 18ms 9 Sep 2022 600th stewSquared 🇺🇸 883 70 22ms 27 Sep 2022 600th orthoplex 🇨🇽 883 70 23ms 9 Oct 2022 600th 5quiwyrm 883 70 17ms 19 Oct 2022 600th myfatemi04 883 70 19ms 4 Nov 2022 600th kevinmchung 883 70 18ms 4 Nov 2022 600th FlorianCassayre 🇫🇷 883 70 18ms 7 Nov 2022 600th fourth-bit 883 70 18ms 29 Nov 2022 600th QuincyNash 🇺🇸 883 70 18ms 29 Nov 2022 600th aksyristos 883 70 18ms 25 Dec 2022 600th thizanne 883 70 20ms 27 Dec 2022 600th Alex-x90 🇺🇸 883 70 21ms 20 Jan 2023 600th bob-th 883 70 18ms 24 Jan 2023 600th SirFireball3521 883 70 17ms 25 Jan 2023 600th stefangimmillaro 883 70 19ms 6 Feb 2023 600th Seek64 🇩🇪 883 70 18ms 7 Feb 2023 600th FieryIceStickie 883 70 19ms 3 Apr 2023 600th MeWhenI 🇻🇦 883 70 19ms 30 Apr 2023 600th fgrosshans 🇫🇷 883 70 18ms 5 May 2023 600th Shanethegamer 🇺🇸 883 70 21ms 25 May 2023 600th InigoK 🇺🇸 883 70 19ms 14 Jun 2023 600th quimey 883 70 15ms 15 Jun 2023 600th CornerMercury 🇬🇧 883 70 19ms 19 Jun 2023 600th ndren 883 70 20ms 2 Aug 2023 600th janbehrens 🇩🇪 883 70 19ms 24 Nov 2023 600th namelessiw 883 70 20ms 9 Jan 2024 First Prev 561–640 of 3,526 Next Last