The Calendar hole will go live in approximately 8 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 881st aditsu 859 77 3,684ms 23 Nov 2025 882nd Yewzir 🇧🇪 858 65 4ms 9 Oct 2023 882nd MeWhenI 🇻🇦 858 65 3ms 10 Oct 2023 884th Shanethegamer 🇺🇸 858 83 1,354ms 4 May 2022 885th frankgraziano 858 198 113ms 14 Oct 2025 886th dokutan 857 79 11ms 27 Apr 2024 887th dokutan 857 93 428ms 27 Sep 2025 888th henrydukepickle 857 97 118ms 8 Jul 2025 889th yeminghan2021 857 99 86ms 3 Feb 2025 890th DialFrost 🇸🇬 857 162 1,753ms 13 Sep 2025 890th emgordon154 857 162 1,669ms 17 Sep 2025 892nd SirBogman 🇺🇸 856 55 36ms 5 May 2022 892nd olivermrose 🇺🇸 856 55 38ms 6 May 2022 892nd 4hg 🇺🇸 856 55 59ms 24 Aug 2022 892nd DialFrost 🇸🇬 856 55 42ms 1 Jan 2023 892nd error256 856 55 44ms 4 May 2024 897th JayXon 🇺🇸 856 56 998ms 9 May 2022 898th mtirado1 856 74 83ms 24 Dec 2022 898th Betuaredead 856 74 81ms 6 Jan 2023 898th KatieLG 🇬🇧 856 74 81ms 15 Jan 2023 898th bwat2 856 74 84ms 31 Mar 2023 898th stackotter 856 74 82ms 29 May 2023 898th ovs-code 🇩🇪 856 74 82ms 17 Apr 2024 898th madeforlosers 856 74 80ms 21 Nov 2024 905th eshilo-draper 856 91 365ms 4 Sep 2022 905th ericlangedijk 🇸🇮 856 91 389ms 23 May 2023 905th KatieLG 🇬🇧 856 91 382ms 30 Apr 2024 905th Mikey-Beep 🇬🇧 856 91 341ms 3 Sep 2024 909th DialFrost 🇸🇬 855 61 418ms 21 Jan 2024 910th Shanethegamer 🇺🇸 855 99 24ms 27 Apr 2023 911th ovs-code 🇩🇪 853 62 131ms 3 Aug 2024 911th MeWhenI 🇻🇦 853 62 134ms 25 Oct 2024 911th Shanethegamer 🇺🇸 853 62 141ms 19 Dec 2024 914th Shanethegamer 🇺🇸 853 85 411ms 18 May 2022 914th GrayJoKing 🇦🇺 853 85 404ms 20 May 2022 916th JRaspass 🇬🇧 852 46 423ms 4 May 2022 916th Natanaelel 🇸🇪 852 46 439ms 4 May 2022 918th retrohun 852 64 6ms 6 Nov 2022 918th Re-Adventures 🇮🇳 852 64 5ms 7 Nov 2022 918th stellartux 852 64 5ms 26 Dec 2023 918th bac0id 852 64 5ms 29 Jun 2024 918th snoozingnewt 🇨🇦 852 64 5ms 1 Sep 2024 918th albanian-laundromat 852 64 5ms 22 Sep 2025 924th the-zammers 852 68 172ms 2 Oct 2023 925th DialFrost 🇸🇬 852 87 42ms 8 days ago 926th janAkali 🇷🇺 851 77 123ms 12 Feb 2025 927th lynn 851 96 29ms 11 Jul 2023 928th Schmitt-Very-Cool 851 98 435ms 26 Sep 2025 929th inventshah 850 74 2ms 4 May 2022 929th undersquire 850 74 2ms 24 Jun 2023 929th rdmsr 850 74 2ms 24 Jun 2023 929th Bmrl7 850 74 2ms 9 Jul 2023 929th Vinterion 850 74 4ms 6 Nov 2023 929th Herbert00709 🇵🇱 850 74 2ms 22 Dec 2023 935th krcs 🇵🇱 849 53 282ms 9 May 2022 935th ryanlanegit 849 53 301ms 19 Jun 2022 935th sisyphus-ppcg 🇦🇺 849 53 456ms 15 Aug 2022 938th randolchance 849 63 11ms 8 Jan 2023 938th CatsAreFluffy 849 63 10ms 18 Feb 2023 938th amiralitaheri 849 63 10ms 23 Feb 2023 938th RuyiLi 849 63 9ms 1 Apr 2023 938th TaserTheFox 🇺🇸 849 63 10ms 25 May 2023 938th pfysches-boop 849 63 9ms 6 Aug 2023 938th mhgockel 849 63 10ms 19 Aug 2023 938th NickTheEASDude 🇺🇸 849 63 10ms 18 Jan 2024 938th 823126 849 63 14ms 14 Nov 2024 938th Palladium02 849 63 9ms 12 May 2025 938th 4very 849 63 10ms 10 Jun 2025 938th Ultra814 849 63 9ms 21 Aug 2025 950th MeWhenI 🇻🇦 849 71 106ms 13 Dec 2022 951st DialFrost 🇸🇬 848 66 107ms 7 Apr 2025 951st KasperKivimaeki 🇫🇮 848 66 9ms 25 hours ago 953rd SirBogman 🇺🇸 848 89 38ms 4 May 2022 954th Shanethegamer 🇺🇸 848 98 119ms 26 Oct 2022 954th emgordon154 848 98 121ms 18 Feb 2025 956th jared-hughes 848 100 69ms 20 Jul 2022 956th ZakkkkAttackkkk 🇵🇭 848 100 71ms 10 Aug 2022 956th Walter225 848 100 70ms 25 Jul 2023 959th AdamHe17 847 73 20ms 31 May 2022 959th AliceFord 847 73 19ms 2 Jun 2022 First Prev 881–960 of 3,499 Next Last