The Calendar hole will go live in approximately 5 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 605th CornerMercury 🇬🇧 883 70 19ms 19 Jun 2023 605th ndren 883 70 20ms 2 Aug 2023 605th janbehrens 🇩🇪 883 70 19ms 24 Nov 2023 605th namelessiw 883 70 20ms 9 Jan 2024 605th mathisfun271 883 70 18ms 13 Feb 2024 605th Just4FunCoder 883 70 20ms 17 Feb 2024 605th ThijsLuttikhuis 883 70 19ms 3 Mar 2024 605th elgan65536 883 70 19ms 5 Mar 2024 605th jtaxen 883 70 18ms 1 Apr 2024 605th HumanoidCPU 883 70 19ms 6 May 2024 605th abc7-12 883 70 18ms 6 May 2024 605th ahmetdemirag 🇨🇾 883 70 18ms 9 Jun 2024 605th FranklinJiaChen 883 70 21ms 4 Jul 2024 605th 5cw 🇺🇸 883 70 18ms 13 Jul 2024 605th CaedenHarper 🇨🇦 883 70 18ms 3 Aug 2024 605th emgordon154 883 70 19ms 5 Aug 2024 605th dokutan 883 70 23ms 9 Aug 2024 605th jatloe 883 70 19ms 26 Aug 2024 605th lgrandco 883 70 19ms 9 Oct 2024 605th snydej 883 70 19ms 21 Nov 2024 605th erikji 883 70 19ms 4 Feb 2025 605th CutSandstone 883 70 19ms 4 Feb 2025 605th albanian-laundromat 883 70 19ms 12 Apr 2025 605th xsot 🇸🇬 883 70 22ms 3 May 2025 605th fuzzylojik-golf 🇺🇸 883 70 19ms 14 Jun 2025 605th smilesformiles3 883 70 19ms 14 Jun 2025 605th KasperKivimaeki 🇫🇮 883 70 19ms 30 Jun 2025 605th adaGrad1 883 70 18ms 10 Aug 2025 605th EthanJantz 883 70 18ms 10 Aug 2025 605th qpwoeirut 883 70 16ms 10 Aug 2025 605th katss2 883 70 19ms 17 Aug 2025 605th intgrah 883 70 18ms 23 Sep 2025 605th ryyyn 🇺🇸 883 70 18ms 29 Oct 2025 605th luuumine 🇫🇷 883 70 18ms 3 Nov 2025 605th Babafaba 883 70 19ms 7 Nov 2025 605th commandblockguy 🇺🇸 883 70 19ms 16 Nov 2025 605th hellopir2 883 70 22ms 23 Nov 2025 605th bzijlema 🇳🇱 883 70 20ms 23 days ago 679th Shanethegamer 🇺🇸 882 51 426ms 15 May 2023 680th GrayJoKing 🇦🇺 882 60 133ms 24 Oct 2024 681st GrayJoKing 🇦🇺 882 84 37ms 19 Jun 2022 681st primo-ppcg 🇹🇭 882 84 36ms 29 Jun 2022 683rd Shanethegamer 🇺🇸 881 73 90ms 8 May 2025 683rd DialFrost 🇸🇬 881 73 83ms 3 Jun 2025 683rd edsrzf 🇳🇿 881 73 98ms 4 Jul 2025 686th Shanethegamer 🇺🇸 881 142 511ms 27 Mar 2025 686th DialFrost 🇸🇬 881 142 490ms 28 Mar 2025 686th emgordon154 881 142 395ms 10 Apr 2025 686th GolfingSuccess 🇬🇷 881 142 463ms 20 days ago 690th primo-ppcg 🇹🇭 881 193 107ms 14 Aug 2025 691st dokutan 880 62 5ms 28 Apr 2025 692nd johnnythedoggie 880 72 91ms 13 May 2022 692nd kaascevich 880 72 90ms 8 Jul 2025 694th Shanethegamer 🇺🇸 878 66 172ms 4 May 2022 694th scpchicken 🇵🇼 878 66 254ms 5 May 2022 694th sisyphus-ppcg 🇦🇺 878 66 174ms 6 May 2022 694th Natanaelel 🇸🇪 878 66 144ms 15 Jun 2022 694th Z-snails 878 66 254ms 27 Feb 2023 694th Jeremy-Stafford 878 66 258ms 27 Feb 2023 694th alomiF 878 66 293ms 1 Sep 2023 694th btnlq 878 66 145ms 17 Oct 2023 702nd DialFrost 🇸🇬 878 86 40ms 24 Oct 2024 702nd stefangimmillaro 878 86 39ms 14 Jan 2025 704th emgordon154 878 97 105ms 22 days ago 705th JayXon 🇺🇸 878 158 1,772ms 14 Sep 2025 706th c0d3-4-F00d 🇩🇪 877 61 10ms 6 May 2022 706th jackkav 877 61 10ms 26 Jun 2022 706th TechNolaByte 877 61 10ms 6 Jul 2022 706th Heathcorp 🇦🇺 877 61 9ms 17 Jul 2022 706th C0de5mith 🇺🇸 877 61 11ms 3 Aug 2022 706th sebipopa 🇷🇴 877 61 10ms 18 Aug 2022 706th moikaturns 🇬🇧 877 61 9ms 25 Sep 2022 706th FlorianCassayre 🇫🇷 877 61 10ms 27 Sep 2022 706th Mazn3k 877 61 10ms 1 Feb 2023 706th tvcv901 877 61 10ms 22 Mar 2023 706th unfinishedprogram 877 61 10ms 19 Jul 2023 706th snoozingnewt 🇨🇦 877 61 10ms 23 Sep 2023 706th funnyboy-roks 877 61 10ms 9 May 2024 706th bac0id 877 61 10ms 29 Jun 2024 706th madex 🇩🇪 877 61 10ms 9 Jul 2024 First Prev 641–720 of 3,506 Next Last