The Calendar hole will go live in approximately 9 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 873rd Kacarott 🇦🇺 859 72 16ms 24 Mar 2023 873rd Fracture17 859 72 20ms 8 Apr 2023 873rd ayushdewan 859 72 23ms 7 May 2023 873rd PeterTillema 🇳🇱 859 72 24ms 17 Oct 2023 873rd Glinte 859 72 24ms 11 Dec 2023 873rd nanatsu8 859 72 24ms 11 May 2024 873rd thej10n 859 72 18ms 12 Jun 2024 873rd tobeannouncd 859 72 16ms 25 Apr 2025 873rd YAJUE114514 859 72 16ms 15 Aug 2025 873rd snoozingnewt 🇨🇦 859 72 23ms 16 days ago 891st aditsu 859 77 3,684ms 23 Nov 2025 892nd Yewzir 🇧🇪 858 65 4ms 9 Oct 2023 892nd MeWhenI 🇻🇦 858 65 3ms 10 Oct 2023 894th Shanethegamer 🇺🇸 858 83 1,354ms 4 May 2022 895th frankgraziano 858 198 113ms 14 Oct 2025 896th frosster 857 76 7ms 12 May 2023 896th kyleclaassen 857 76 7ms 20 May 2023 896th NickTheEASDude 🇺🇸 857 76 6ms 7 May 2024 896th koipondx86 857 76 7ms 8 Nov 2024 900th dokutan 857 93 428ms 27 Sep 2025 901st henrydukepickle 857 97 118ms 8 Jul 2025 902nd yeminghan2021 857 99 86ms 3 Feb 2025 903rd DialFrost 🇸🇬 857 162 1,753ms 13 Sep 2025 903rd emgordon154 857 162 1,669ms 17 Sep 2025 905th SirBogman 🇺🇸 856 55 36ms 5 May 2022 905th olivermrose 🇺🇸 856 55 38ms 6 May 2022 905th 4hg 🇺🇸 856 55 59ms 24 Aug 2022 905th DialFrost 🇸🇬 856 55 42ms 1 Jan 2023 905th error256 856 55 44ms 4 May 2024 910th JayXon 🇺🇸 856 56 998ms 9 May 2022 911th mtirado1 856 74 83ms 24 Dec 2022 911th Betuaredead 856 74 81ms 6 Jan 2023 911th KatieLG 🇬🇧 856 74 81ms 15 Jan 2023 911th bwat2 856 74 84ms 31 Mar 2023 911th stackotter 856 74 82ms 29 May 2023 911th ovs-code 🇩🇪 856 74 82ms 17 Apr 2024 911th madeforlosers 856 74 80ms 21 Nov 2024 918th eshilo-draper 856 91 365ms 4 Sep 2022 918th ericlangedijk 🇸🇮 856 91 389ms 23 May 2023 918th KatieLG 🇬🇧 856 91 382ms 30 Apr 2024 918th Mikey-Beep 🇬🇧 856 91 341ms 3 Sep 2024 922nd DialFrost 🇸🇬 855 61 418ms 21 Jan 2024 923rd Shanethegamer 🇺🇸 855 99 24ms 27 Apr 2023 924th ovs-code 🇩🇪 853 62 131ms 3 Aug 2024 924th MeWhenI 🇻🇦 853 62 134ms 25 Oct 2024 924th Shanethegamer 🇺🇸 853 62 141ms 19 Dec 2024 927th Shanethegamer 🇺🇸 853 85 411ms 18 May 2022 927th GrayJoKing 🇦🇺 853 85 404ms 20 May 2022 929th JRaspass 🇬🇧 852 46 351ms 4 May 2022 929th Natanaelel 🇸🇪 852 46 542ms 4 May 2022 931st retrohun 852 64 6ms 6 Nov 2022 931st Re-Adventures 🇮🇳 852 64 5ms 7 Nov 2022 931st stellartux 852 64 5ms 26 Dec 2023 931st bac0id 852 64 5ms 29 Jun 2024 931st snoozingnewt 🇨🇦 852 64 5ms 1 Sep 2024 931st albanian-laundromat 852 64 5ms 22 Sep 2025 937th the-zammers 852 68 172ms 2 Oct 2023 938th DialFrost 🇸🇬 852 87 42ms 7 days ago 939th janAkali 🇷🇺 851 77 123ms 12 Feb 2025 940th lynn 851 96 29ms 11 Jul 2023 941st Schmitt-Very-Cool 851 98 435ms 26 Sep 2025 942nd inventshah 850 74 2ms 4 May 2022 942nd undersquire 850 74 2ms 24 Jun 2023 942nd rdmsr 850 74 2ms 24 Jun 2023 942nd Bmrl7 850 74 2ms 9 Jul 2023 942nd Vinterion 850 74 4ms 6 Nov 2023 942nd Herbert00709 🇵🇱 850 74 2ms 22 Dec 2023 948th krcs 🇵🇱 849 53 282ms 9 May 2022 948th ryanlanegit 849 53 301ms 19 Jun 2022 948th sisyphus-ppcg 🇦🇺 849 53 456ms 15 Aug 2022 951st randolchance 849 63 11ms 8 Jan 2023 951st CatsAreFluffy 849 63 10ms 18 Feb 2023 951st amiralitaheri 849 63 10ms 23 Feb 2023 951st RuyiLi 849 63 9ms 1 Apr 2023 951st TaserTheFox 🇺🇸 849 63 10ms 25 May 2023 951st pfysches-boop 849 63 9ms 6 Aug 2023 951st mhgockel 849 63 10ms 19 Aug 2023 951st NickTheEASDude 🇺🇸 849 63 10ms 18 Jan 2024 951st 823126 849 63 14ms 14 Nov 2024 951st Palladium02 849 63 9ms 12 May 2025 First Prev 881–960 of 3,530 Next Last