The Calendar hole will go live in approximately 10 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 874th CaedenHarper 🇨🇦 846 73 2ms 28 Sep 2025 874th prestosilver 🇺🇸 846 73 2ms 18 days ago 883rd DialFrost 🇸🇬 846 87 42ms 6 days ago 884th Natanaelel 🇸🇪 845 57 417ms 17 Jan 2024 884th Kacarott 🇦🇺 845 57 394ms 10 Sep 2024 884th albanian-laundromat 845 57 494ms 7 Oct 2025 887th retrohun 845 64 6ms 6 Nov 2022 887th Re-Adventures 🇮🇳 845 64 5ms 7 Nov 2022 887th stellartux 845 64 5ms 26 Dec 2023 887th bac0id 845 64 5ms 29 Jun 2024 887th snoozingnewt 🇨🇦 845 64 5ms 1 Sep 2024 887th albanian-laundromat 845 64 5ms 22 Sep 2025 893rd lynn 845 96 29ms 11 Jul 2023 894th Shanethegamer 🇺🇸 845 98 119ms 26 Oct 2022 894th emgordon154 845 98 121ms 18 Feb 2025 896th jared-hughes 845 100 69ms 20 Jul 2022 896th ZakkkkAttackkkk 🇵🇭 845 100 71ms 10 Aug 2022 896th Walter225 845 100 70ms 25 Jul 2023 899th janAkali 🇷🇺 844 77 123ms 12 Feb 2025 900th bschorno 844 92 366ms 12 Oct 2022 900th ChrisTheisen 844 92 339ms 14 Dec 2022 900th kellantech 844 92 363ms 4 Jul 2023 900th Mezzofloat 844 92 377ms 26 Aug 2023 900th Maximizer02 844 92 360ms 1 Oct 2023 900th madeforlosers 844 92 365ms 21 Nov 2024 900th ChromaChroma 844 92 354ms 7 Oct 2025 900th snoozingnewt 🇨🇦 844 92 379ms 8 Oct 2025 908th DialFrost 🇸🇬 843 66 189ms 7 Apr 2025 909th dokutan 843 93 428ms 27 Sep 2025 910th krcs 🇵🇱 842 53 282ms 9 May 2022 910th ryanlanegit 842 53 301ms 19 Jun 2022 910th sisyphus-ppcg 🇦🇺 842 53 456ms 15 Aug 2022 913th MeWhenI 🇻🇦 842 71 106ms 13 Dec 2022 914th SirBogman 🇺🇸 842 89 38ms 4 May 2022 915th error256 841 81 71ms 13 Sep 2024 916th CLOStrophobic 🇮🇹 841 89 42ms 14 Feb 2025 917th kmathis22 841 100 31ms 13 Nov 2025 918th raszpi 🇭🇺 840 77 103ms 1 Sep 2023 919th eshilo-draper 839 75 86ms 6 Sep 2022 919th kmathis22 839 75 79ms 5 Sep 2025 921st sean-niemann 🇺🇸 839 76 107ms 8 Oct 2024 922nd beardotpdf 839 99 346ms 9 days ago 923rd emplv 🇱🇻 839 124 25ms 31 Oct 2022 924th Codsilla 🇨🇦 838 51 266ms 1 Jul 2022 925th frankgraziano 838 66 4ms 20 Apr 2025 926th Andriamanitra 🇫🇮 838 83 12ms 17 Apr 2023 926th Natanaelel 🇸🇪 838 83 12ms 8 Jul 2023 928th MeWhenI 🇻🇦 838 164 1,639ms 7 Nov 2025 929th ovs-code 🇩🇪 837 85 15ms 11 Dec 2023 930th dokutan 837 88 39ms 9 Jun 2024 931st Steffan153 🇫🇮 837 97 29ms 18 Jan 2023 932nd CatsAreFluffy 837 101 54ms 18 Feb 2023 932nd annaproxy 837 101 70ms 9 May 2023 932nd wojtekmal 837 101 78ms 15 Nov 2023 932nd HumanoidCPU 837 101 83ms 6 May 2024 932nd eMGeeneer 837 101 449ms 27 Jun 2024 932nd bac0id 837 101 77ms 29 Jun 2024 932nd michaelmoynihan 837 101 508ms 3 Sep 2025 932nd snoozingnewt 🇨🇦 837 101 517ms 6 Oct 2025 940th SirBogman 🇺🇸 835 36 14ms 5 May 2022 940th Natanaelel 🇸🇪 835 36 87ms 15 Jun 2022 940th Steffan153 🇫🇮 835 36 91ms 18 Jan 2023 940th codereport 🇨🇦 835 36 9ms 1 Jun 2024 940th GolfinK 835 36 9ms 21 Nov 2024 940th lifthrasiir 🇰🇷 835 36 10ms 1 Dec 2024 940th GolfingSuccess 🇬🇷 835 36 11ms 20 Mar 2025 947th scpchicken 🇵🇼 835 55 10ms 4 May 2022 947th SirBogman 🇺🇸 835 55 6ms 5 May 2022 947th Shanethegamer 🇺🇸 835 55 6ms 19 May 2023 947th DialFrost 🇸🇬 835 55 10ms 14 Feb 2025 951st ChiefChippy2 835 56 51ms 4 May 2022 951st aksyristos 835 56 42ms 29 Jan 2023 951st anter69 🇭🇺 835 56 38ms 12 Feb 2024 951st 3dm4n 🇫🇮 835 56 38ms 11 Mar 2024 951st lgrandco 835 56 43ms 9 Oct 2024 951st tatzyr 🇯🇵 835 56 43ms 10 Dec 2024 951st D-MOVE 🇵🇭 835 56 49ms 12 days ago 958th inverseLorentz 🇦🇺 835 69 156ms 3 Jun 2024 958th Yewzir 🇧🇪 835 69 118ms 24 Dec 2024 958th CLOStrophobic 🇮🇹 835 69 170ms 28 May 2025 First Prev 881–960 of 3,506 Next Last