The Calendar hole will go live in approximately 12 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 481st ovs-code 🇩🇪 896 89 438ms 24 Jul 2024 481st jipsong 🇩🇪 896 89 467ms 7 Apr 2025 483rd MichalMarsalek 🇨🇿 895 87 366ms 5 May 2022 483rd Kloppermand 🇩🇰 895 87 375ms 7 Oct 2022 483rd bwat2 895 87 348ms 6 Apr 2023 486th Shanethegamer 🇺🇸 894 61 5ms 31 Oct 2022 486th MeWhenI 🇻🇦 894 61 5ms 4 Nov 2022 488th JayXon 🇺🇸 894 74 4,306ms 14 Nov 2024 489th oeb25 894 93 120ms 16 May 2022 489th snobee 🇨🇦 894 93 119ms 8 Dec 2022 489th logvp 894 93 120ms 2 Jan 2024 489th elgan65536 894 93 120ms 5 Mar 2024 489th smartiel 894 93 124ms 12 Aug 2024 489th trist224 🇫🇷 894 93 122ms 12 Aug 2024 489th nullie 894 93 119ms 19 Dec 2024 489th lolgeny 894 93 116ms 22 Feb 2025 497th m-tkach 🇺🇦 894 117 25ms 7 May 2022 497th Lydxn 🇨🇦 894 117 26ms 7 May 2022 499th Yewzir 🇧🇪 893 72 92ms 20 Nov 2025 500th GolfingSuccess 🇬🇷 893 95 74ms 5 May 2022 500th Alex-x90 🇺🇸 893 95 57ms 4 Dec 2022 500th Mandrzejy 🇵🇱 893 95 67ms 22 Mar 2024 503rd Steffan153 🇫🇮 892 52 7ms 31 Dec 2022 504th DialFrost 🇸🇬 892 56 863ms 1 Sep 2025 505th KatieLG 🇬🇧 892 60 10ms 4 May 2022 505th ScottHamper 892 60 10ms 5 May 2022 505th Re-Adventures 🇮🇳 892 60 10ms 5 May 2022 505th 0x24a537r9 892 60 10ms 29 Jul 2022 505th stefangabos 🇷🇴 892 60 10ms 19 Aug 2022 505th eranws 892 60 10ms 10 Sep 2022 505th GeorgeStechman 🇬🇧 892 60 10ms 26 Sep 2022 505th BloodStormKnight 892 60 10ms 15 Oct 2022 505th dzshn 892 60 10ms 3 Dec 2022 505th biocommando 🇫🇮 892 60 10ms 20 Dec 2022 505th Betuaredead 892 60 9ms 5 Jan 2023 505th piano-miles 892 60 9ms 16 Jan 2023 505th Yewzir 🇧🇪 892 60 10ms 12 Feb 2023 505th shellbertt 🇨🇦 892 60 10ms 26 Feb 2023 505th zakariamouhid 892 60 10ms 20 May 2023 505th raphaelimahorn 892 60 10ms 23 Aug 2023 505th jbt 892 60 9ms 25 Dec 2023 505th olleicua 🇺🇸 892 60 10ms 15 Feb 2024 505th HumanoidCPU 892 60 10ms 3 May 2024 505th dokutan 892 60 10ms 13 Aug 2024 505th LostSyntax21 🇬🇧 892 60 11ms 10 Sep 2024 505th xyangst 892 60 10ms 28 Sep 2024 505th a6166231 🇨🇳 892 60 9ms 15 May 2025 505th Protothor 892 60 10ms 8 Jul 2025 505th SebassNoob 892 60 10ms 5 Aug 2025 505th Yax42 🇫🇷 892 60 10ms 5 Sep 2025 505th levinwinter 892 60 10ms 22 Oct 2025 505th Cube14yt 892 60 10ms 16 Nov 2025 505th gigaprofisi 🇺🇸 892 60 10ms 17 Nov 2025 534th stefangimmillaro 892 71 91ms 2 Oct 2022 534th Steffan153 🇫🇮 892 71 96ms 23 Feb 2023 534th Shanethegamer 🇺🇸 892 71 90ms 16 May 2023 534th sean-niemann 🇺🇸 892 71 89ms 12 Jul 2024 538th RockOfStone 892 73 4ms 20 Oct 2025 539th Lydxn 🇨🇦 892 108 263ms 6 May 2022 539th CaedenHarper 🇨🇦 892 108 308ms 5 Oct 2025 541st lynn 891 65 283ms 5 May 2022 541st GrayJoKing 🇦🇺 891 65 250ms 5 May 2022 541st Sakisan 🇧🇪 891 65 178ms 6 May 2022 541st JayXon 🇺🇸 891 65 311ms 17 Oct 2022 541st Steffan153 🇫🇮 891 65 185ms 12 Nov 2022 541st tobeannouncd 891 65 312ms 25 Apr 2025 541st sean-niemann 🇺🇸 891 65 168ms 9 Jun 2025 548th GrayJoKing 🇦🇺 891 77 96ms 13 Sep 2024 549th DialFrost 🇸🇬 891 95 29ms 10 Dec 2024 550th canissimia 🇦🇶 891 110 2,640ms 20 Feb 2023 551st jared-hughes 891 130 23ms 15 Dec 2024 552nd primo-ppcg 🇹🇭 890 52 297ms 5 May 2022 552nd dvargas46 🇺🇸 890 52 92ms 22 Dec 2022 554th canissimia 🇦🇶 890 204 16ms 25 Nov 2023 555th mousetail 🇳🇱 888 41 66ms 29 Aug 2025 556th MeWhenI 🇻🇦 888 53 58ms 1 Jun 2022 556th stefangimmillaro 888 53 56ms 2 Oct 2022 556th Haksell 🇦🇶 888 53 46ms 22 Feb 2023 559th primo-ppcg 🇹🇭 888 85 39ms 14 Jan 2025 559th MeWhenI 🇻🇦 888 85 41ms 21 Apr 2025 First Prev 481–560 of 3,526 Next Last