The Calendar hole will go live in approximately 4 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 880th Re-Adventures 🇮🇳 845 64 5ms 7 Nov 2022 880th stellartux 845 64 5ms 26 Dec 2023 880th bac0id 845 64 5ms 29 Jun 2024 880th snoozingnewt 🇨🇦 845 64 5ms 1 Sep 2024 880th albanian-laundromat 845 64 5ms 22 Sep 2025 886th lynn 845 96 29ms 11 Jul 2023 887th Shanethegamer 🇺🇸 845 98 119ms 26 Oct 2022 887th emgordon154 845 98 121ms 18 Feb 2025 889th janAkali 🇷🇺 844 77 123ms 12 Feb 2025 890th frosster 844 80 11ms 2 days ago 891st bschorno 844 92 366ms 12 Oct 2022 891st ChrisTheisen 844 92 339ms 14 Dec 2022 891st kellantech 844 92 363ms 4 Jul 2023 891st Mezzofloat 844 92 377ms 26 Aug 2023 891st Maximizer02 844 92 360ms 1 Oct 2023 891st madeforlosers 844 92 365ms 21 Nov 2024 891st ChromaChroma 844 92 354ms 7 Oct 2025 891st snoozingnewt 🇨🇦 844 92 374ms 8 Oct 2025 899th DialFrost 🇸🇬 843 66 85ms 7 Apr 2025 899th KasperKivimaeki 🇫🇮 843 66 8ms 5 days ago 901st dokutan 843 93 428ms 27 Sep 2025 902nd krcs 🇵🇱 842 53 282ms 9 May 2022 902nd ryanlanegit 842 53 260ms 19 Jun 2022 902nd sisyphus-ppcg 🇦🇺 842 53 402ms 15 Aug 2022 905th MeWhenI 🇻🇦 842 71 106ms 13 Dec 2022 906th SirBogman 🇺🇸 842 89 38ms 4 May 2022 907th error256 841 81 68ms 13 Sep 2024 908th CLOStrophobic 🇮🇹 841 89 42ms 14 Feb 2025 909th kmathis22 841 100 31ms 13 Nov 2025 910th raszpi 🇭🇺 840 77 103ms 1 Sep 2023 911th eshilo-draper 839 75 84ms 6 Sep 2022 911th kmathis22 839 75 79ms 5 Sep 2025 913th sean-niemann 🇺🇸 839 76 107ms 8 Oct 2024 914th beardotpdf 839 99 346ms 15 days ago 915th emplv 🇱🇻 839 124 25ms 31 Oct 2022 916th Codsilla 🇨🇦 838 51 266ms 1 Jul 2022 917th frankgraziano 838 66 4ms 20 Apr 2025 918th Andriamanitra 🇫🇮 838 83 12ms 17 Apr 2023 918th Natanaelel 🇸🇪 838 83 12ms 8 Jul 2023 920th MeWhenI 🇻🇦 838 164 1,639ms 7 Nov 2025 921st ovs-code 🇩🇪 837 85 15ms 11 Dec 2023 922nd dokutan 837 88 39ms 9 Jun 2024 923rd Steffan153 🇫🇮 837 97 29ms 18 Jan 2023 924th CatsAreFluffy 837 101 54ms 18 Feb 2023 924th annaproxy 837 101 59ms 9 May 2023 924th wojtekmal 837 101 61ms 15 Nov 2023 924th HumanoidCPU 837 101 60ms 6 May 2024 924th eMGeeneer 837 101 412ms 27 Jun 2024 924th bac0id 837 101 60ms 29 Jun 2024 924th michaelmoynihan 837 101 413ms 3 Sep 2025 924th snoozingnewt 🇨🇦 837 101 421ms 6 Oct 2025 932nd SirBogman 🇺🇸 835 36 14ms 5 May 2022 932nd Natanaelel 🇸🇪 835 36 87ms 15 Jun 2022 932nd Steffan153 🇫🇮 835 36 91ms 18 Jan 2023 932nd codereport 🇨🇦 835 36 9ms 1 Jun 2024 932nd GolfinK 835 36 9ms 21 Nov 2024 932nd lifthrasiir 🇰🇷 835 36 10ms 1 Dec 2024 932nd GolfingSuccess 🇬🇷 835 36 11ms 20 Mar 2025 939th scpchicken 🇵🇼 835 55 10ms 4 May 2022 939th SirBogman 🇺🇸 835 55 6ms 5 May 2022 939th Shanethegamer 🇺🇸 835 55 6ms 19 May 2023 939th DialFrost 🇸🇬 835 55 10ms 14 Feb 2025 943rd ChiefChippy2 835 56 41ms 4 May 2022 943rd aksyristos 835 56 42ms 29 Jan 2023 943rd anter69 🇭🇺 835 56 41ms 12 Feb 2024 943rd 3dm4n 🇫🇮 835 56 42ms 11 Mar 2024 943rd lgrandco 835 56 43ms 9 Oct 2024 943rd tatzyr 🇯🇵 835 56 42ms 10 Dec 2024 943rd D-MOVE 🇵🇭 835 56 41ms 19 days ago 950th inverseLorentz 🇦🇺 835 69 156ms 3 Jun 2024 950th Yewzir 🇧🇪 835 69 118ms 24 Dec 2024 950th CLOStrophobic 🇮🇹 835 69 170ms 28 May 2025 953rd p-vf 🇨🇭 835 93 337ms 24 Jun 2022 953rd Smetalo 835 93 384ms 25 Aug 2022 953rd malworthy 835 93 360ms 19 Aug 2024 956th moustave 834 67 23ms 7 Nov 2024 957th Alex-x90 🇺🇸 834 74 2ms 4 Dec 2022 957th undersquire 834 74 2ms 24 Jun 2023 957th rdmsr 834 74 2ms 24 Jun 2023 957th Bmrl7 834 74 2ms 9 Jul 2023 First Prev 881–960 of 3,486 Next Last