The Calendar hole will go live in approximately 8 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 478th elgan65536 894 93 120ms 5 Mar 2024 478th smartiel 894 93 124ms 12 Aug 2024 478th trist224 🇫🇷 894 93 122ms 12 Aug 2024 478th nullie 894 93 119ms 19 Dec 2024 478th lolgeny 894 93 116ms 22 Feb 2025 486th m-tkach 🇺🇦 894 117 25ms 7 May 2022 486th Lydxn 🇨🇦 894 117 26ms 7 May 2022 488th Yewzir 🇧🇪 893 72 92ms 20 Nov 2025 489th GolfingSuccess 🇬🇷 893 95 74ms 5 May 2022 489th Alex-x90 🇺🇸 893 95 57ms 4 Dec 2022 489th Mandrzejy 🇵🇱 893 95 67ms 22 Mar 2024 492nd Steffan153 🇫🇮 892 52 7ms 31 Dec 2022 493rd DialFrost 🇸🇬 892 56 863ms 1 Sep 2025 494th KatieLG 🇬🇧 892 60 10ms 4 May 2022 494th ScottHamper 892 60 10ms 5 May 2022 494th Re-Adventures 🇮🇳 892 60 10ms 5 May 2022 494th 0x24a537r9 892 60 10ms 29 Jul 2022 494th stefangabos 🇷🇴 892 60 10ms 19 Aug 2022 494th eranws 892 60 10ms 10 Sep 2022 494th GeorgeStechman 🇬🇧 892 60 10ms 26 Sep 2022 494th BloodStormKnight 892 60 10ms 15 Oct 2022 494th dzshn 892 60 10ms 3 Dec 2022 494th biocommando 🇫🇮 892 60 10ms 20 Dec 2022 494th Betuaredead 892 60 9ms 5 Jan 2023 494th piano-miles 892 60 9ms 16 Jan 2023 494th Yewzir 🇧🇪 892 60 10ms 12 Feb 2023 494th shellbertt 🇨🇦 892 60 10ms 26 Feb 2023 494th zakariamouhid 892 60 10ms 20 May 2023 494th raphaelimahorn 892 60 10ms 23 Aug 2023 494th jbt 892 60 9ms 25 Dec 2023 494th olleicua 🇺🇸 892 60 10ms 15 Feb 2024 494th HumanoidCPU 892 60 10ms 3 May 2024 494th dokutan 892 60 10ms 13 Aug 2024 494th LostSyntax21 🇬🇧 892 60 11ms 10 Sep 2024 494th xyangst 892 60 10ms 28 Sep 2024 494th a6166231 🇨🇳 892 60 9ms 15 May 2025 494th Protothor 892 60 10ms 8 Jul 2025 494th SebassNoob 892 60 10ms 5 Aug 2025 494th Yax42 🇫🇷 892 60 10ms 5 Sep 2025 494th levinwinter 892 60 10ms 22 Oct 2025 494th Cube14yt 892 60 10ms 16 Nov 2025 494th gigaprofisi 🇺🇸 892 60 10ms 17 Nov 2025 494th amazingalek 892 60 14ms 2 days ago 524th stefangimmillaro 892 71 91ms 2 Oct 2022 524th Steffan153 🇫🇮 892 71 96ms 23 Feb 2023 524th Shanethegamer 🇺🇸 892 71 90ms 16 May 2023 524th sean-niemann 🇺🇸 892 71 89ms 12 Jul 2024 528th Lydxn 🇨🇦 892 108 263ms 6 May 2022 528th CaedenHarper 🇨🇦 892 108 308ms 5 Oct 2025 530th lynn 891 65 283ms 5 May 2022 530th GrayJoKing 🇦🇺 891 65 250ms 5 May 2022 530th Sakisan 🇧🇪 891 65 178ms 6 May 2022 530th JayXon 🇺🇸 891 65 311ms 17 Oct 2022 530th Steffan153 🇫🇮 891 65 185ms 12 Nov 2022 530th tobeannouncd 891 65 312ms 25 Apr 2025 530th sean-niemann 🇺🇸 891 65 168ms 9 Jun 2025 537th GrayJoKing 🇦🇺 891 77 96ms 13 Sep 2024 538th DialFrost 🇸🇬 891 95 29ms 10 Dec 2024 539th canissimia 🇦🇶 891 110 2,640ms 20 Feb 2023 540th jared-hughes 891 130 23ms 15 Dec 2024 541st primo-ppcg 🇹🇭 890 52 297ms 5 May 2022 541st dvargas46 🇺🇸 890 52 92ms 22 Dec 2022 543rd canissimia 🇦🇶 890 204 16ms 25 Nov 2023 544th mousetail 🇳🇱 888 41 66ms 29 Aug 2025 545th MeWhenI 🇻🇦 888 53 58ms 1 Jun 2022 545th stefangimmillaro 888 53 56ms 2 Oct 2022 545th Haksell 🇦🇶 888 53 46ms 22 Feb 2023 548th NickTheEASDude 🇺🇸 888 76 6ms 7 May 2024 548th edsrzf 🇳🇿 888 76 9ms 109 mins ago 548th Shanethegamer 🇺🇸 888 76 34ms 107 mins ago 551st primo-ppcg 🇹🇭 888 85 39ms 14 Jan 2025 551st MeWhenI 🇻🇦 888 85 41ms 21 Apr 2025 553rd ovs-code 🇩🇪 887 73 340ms 22 Jul 2023 554th albanian-laundromat 887 94 415ms 24 Sep 2025 554th jkelly467 887 94 544ms 23 Oct 2025 554th HumanoidCPU 887 94 397ms 8 Nov 2025 557th snoozingnewt 🇨🇦 887 96 109ms 19 days ago 558th GolfingSuccess 🇬🇷 886 71 2ms 5 May 2022 558th emplv 🇱🇻 886 71 2ms 5 May 2022 558th JayXon 🇺🇸 886 71 2ms 7 May 2022 First Prev 481–560 of 3,496 Next Last