The Calendar hole will go live in approximately 13 days. Why not try and solve it ahead of time?
Collatz in all languages in chars. 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 Chars Time Submitted 401st edsrzf 🇳🇿 903 72 160ms 3 Jul 2025 402nd Shanethegamer 🇺🇸 903 77 13ms 15 May 2023 403rd marshallward 🇺🇸 903 83 41ms 10 May 2022 404th Betuaredead 902 60 5ms 5 Jan 2023 404th Yewzir 🇧🇪 902 60 5ms 12 Feb 2023 404th Steffan153 🇫🇮 902 60 5ms 23 Feb 2023 404th DialFrost 🇸🇬 902 60 5ms 30 Jul 2024 404th GolfingSuccess 🇬🇷 902 60 5ms 16 Oct 2024 404th sean-niemann 🇺🇸 902 60 9ms 7 Mar 2025 410th edsrzf 🇳🇿 902 83 43ms 14 Jan 2025 410th kg583 🇺🇸 902 83 42ms 14 Feb 2025 412th krcs 🇵🇱 902 86 372ms 10 May 2022 412th billings7 🇬🇧 902 86 347ms 15 May 2022 412th revlayle 🇺🇸 902 86 337ms 7 Dec 2022 412th albanian-laundromat 902 86 383ms 30 Sep 2025 416th m-tkach 🇺🇦 902 90 30ms 7 Dec 2023 417th shellbertt 🇨🇦 901 62 19ms 4 May 2022 417th ZakkkkAttackkkk 🇵🇭 901 62 19ms 5 May 2022 417th annaproxy 901 62 19ms 8 Jun 2022 417th bob-th 901 62 24ms 9 Jul 2022 417th btjones0 901 62 23ms 15 Jul 2022 417th tri1212 🇻🇳 901 62 19ms 18 Jul 2022 417th fredrik-bakke 🇳🇴 901 62 23ms 5 Oct 2022 417th jakobkordez 🇸🇮 901 62 19ms 19 Oct 2022 417th Fishron 901 62 19ms 29 Nov 2022 417th KatieLG 🇬🇧 901 62 22ms 11 Dec 2022 417th ItsMeNoobieboy 901 62 20ms 20 Dec 2022 417th firegene 🇮🇪 901 62 19ms 3 Jan 2023 417th ljweel 901 62 19ms 13 Feb 2023 417th 2011-Chan-Ethan 901 62 18ms 9 Jul 2023 417th elgan65536 901 62 19ms 18 Nov 2023 417th Dataen 901 62 19ms 16 Jan 2024 417th Yewzir 🇧🇪 901 62 49ms 5 Apr 2024 417th cuboids 901 62 20ms 11 Jul 2024 417th wuzekai518 901 62 24ms 26 Jul 2024 417th abhishekg999 901 62 49ms 17 Sep 2024 417th lifthrasiir 🇰🇷 901 62 19ms 16 Nov 2024 417th Artemis21 🇬🇧 901 62 19ms 17 Jan 2025 417th lolgeny 901 62 19ms 22 Feb 2025 417th keelimeguy 🇺🇸 901 62 19ms 15 May 2025 417th Flekay 🇩🇪 901 62 19ms 19 Jun 2025 417th DoubleUynn 901 62 19ms 25 Jun 2025 417th JOrE20 🇺🇸 901 62 17ms 25 days ago 444th GolfingSuccess 🇬🇷 901 64 91ms 14 Dec 2024 444th MeWhenI 🇻🇦 901 64 91ms 24 Dec 2024 444th GrayJoKing 🇦🇺 901 64 92ms 22 days ago 447th kg583 🇺🇸 901 79 24ms 30 Jul 2025 448th Lydxn 🇨🇦 900 64 181ms 1 Apr 2023 449th DialFrost 🇸🇬 900 76 154ms 3 Aug 2025 450th Kacarott 🇦🇺 900 79 117ms 13 Jun 2024 451st stefangimmillaro 900 92 131ms 24 Oct 2023 451st inverseLorentz 🇦🇺 900 92 128ms 27 May 2024 451st sean-niemann 🇺🇸 900 92 125ms 8 Jun 2025 451st ian-h-chamberlain 🇺🇸 900 92 123ms 25 days ago 455th shinh 899 52 38ms 29 Jun 2022 455th MeWhenI 🇻🇦 899 52 60ms 25 Jul 2023 457th MeWhenI 🇻🇦 899 63 184ms 5 May 2022 458th Shanethegamer 🇺🇸 899 72 3ms 4 May 2022 458th jared-hughes 899 72 4ms 4 May 2022 458th Waffle3z 899 72 4ms 5 May 2022 458th Blendi-Goose 899 72 4ms 16 Mar 2025 458th edsrzf 🇳🇿 899 72 5ms 12 Apr 2025 458th sean-niemann 🇺🇸 899 72 3ms 16 Oct 2025 464th michael-pruglo 🇺🇦 899 94 64ms 5 Jul 2022 464th zygoloid 899 94 74ms 5 Aug 2024 466th Lydxn 🇨🇦 898 70 91ms 7 May 2022 467th MeWhenI 🇻🇦 898 71 102ms 20 Aug 2024 468th m-tkach 🇺🇦 898 72 99ms 16 Oct 2022 468th GrayJoKing 🇦🇺 898 72 105ms 22 Oct 2022 468th emplv 🇱🇻 898 72 101ms 27 Oct 2022 468th sean-niemann 🇺🇸 898 72 117ms 7 Mar 2025 472nd Steffan153 🇫🇮 898 82 42ms 1 Apr 2023 472nd sean-niemann 🇺🇸 898 82 42ms 12 Jul 2024 474th Lydxn 🇨🇦 895 69 7ms 12 Sep 2022 474th GrayJoKing 🇦🇺 895 69 7ms 12 Sep 2022 474th btnlq 895 69 7ms 24 Sep 2022 474th trinityy-7 895 69 2ms 7 Aug 2025 478th SirBogman 🇺🇸 892 50 402ms 5 May 2022 478th nwellnhof 🇩🇪 892 50 397ms 3 Jun 2022 478th Lydxn 🇨🇦 892 50 404ms 15 Aug 2022 First Prev 401–480 of 3,502 Next Last