The Calendar hole will go live in approximately 2 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 869th Glinte 859 72 24ms 11 Dec 2023 869th nanatsu8 859 72 24ms 11 May 2024 869th thej10n 859 72 18ms 12 Jun 2024 869th tobeannouncd 859 72 16ms 25 Apr 2025 869th YAJUE114514 859 72 16ms 15 Aug 2025 869th snoozingnewt 🇨🇦 859 72 23ms 23 days ago 887th aditsu 859 77 3,141ms 23 Nov 2025 888th Yewzir 🇧🇪 858 65 4ms 9 Oct 2023 888th MeWhenI 🇻🇦 858 65 3ms 10 Oct 2023 890th Shanethegamer 🇺🇸 858 83 1,354ms 4 May 2022 891st frankgraziano 858 198 108ms 14 Oct 2025 892nd dokutan 857 93 428ms 27 Sep 2025 893rd henrydukepickle 857 97 118ms 8 Jul 2025 894th yeminghan2021 857 99 66ms 3 Feb 2025 895th DialFrost 🇸🇬 857 162 1,753ms 13 Sep 2025 896th SirBogman 🇺🇸 856 55 41ms 5 May 2022 896th olivermrose 🇺🇸 856 55 45ms 6 May 2022 896th 4hg 🇺🇸 856 55 43ms 24 Aug 2022 896th DialFrost 🇸🇬 856 55 45ms 1 Jan 2023 896th error256 856 55 40ms 4 May 2024 901st JayXon 🇺🇸 856 56 998ms 9 May 2022 902nd mtirado1 856 74 83ms 24 Dec 2022 902nd Betuaredead 856 74 81ms 6 Jan 2023 902nd KatieLG 🇬🇧 856 74 81ms 15 Jan 2023 902nd bwat2 856 74 84ms 31 Mar 2023 902nd stackotter 856 74 82ms 29 May 2023 902nd ovs-code 🇩🇪 856 74 82ms 17 Apr 2024 902nd madeforlosers 856 74 80ms 21 Nov 2024 909th eshilo-draper 856 91 365ms 4 Sep 2022 909th ericlangedijk 🇸🇮 856 91 389ms 23 May 2023 909th KatieLG 🇬🇧 856 91 363ms 30 Apr 2024 909th Mikey-Beep 🇬🇧 856 91 341ms 3 Sep 2024 913th DialFrost 🇸🇬 855 61 418ms 21 Jan 2024 914th Shanethegamer 🇺🇸 855 99 24ms 27 Apr 2023 915th ovs-code 🇩🇪 853 62 131ms 3 Aug 2024 915th MeWhenI 🇻🇦 853 62 134ms 25 Oct 2024 915th Shanethegamer 🇺🇸 853 62 141ms 19 Dec 2024 918th Shanethegamer 🇺🇸 853 85 411ms 18 May 2022 918th GrayJoKing 🇦🇺 853 85 404ms 20 May 2022 920th JRaspass 🇬🇧 852 46 349ms 4 May 2022 920th Natanaelel 🇸🇪 852 46 371ms 4 May 2022 922nd retrohun 852 64 6ms 6 Nov 2022 922nd Re-Adventures 🇮🇳 852 64 5ms 7 Nov 2022 922nd stellartux 852 64 5ms 26 Dec 2023 922nd bac0id 852 64 5ms 29 Jun 2024 922nd snoozingnewt 🇨🇦 852 64 5ms 1 Sep 2024 922nd albanian-laundromat 852 64 5ms 22 Sep 2025 928th the-zammers 852 68 172ms 2 Oct 2023 929th DialFrost 🇸🇬 852 87 42ms 14 days ago 930th janAkali 🇷🇺 851 77 123ms 12 Feb 2025 931st lynn 851 96 29ms 11 Jul 2023 932nd Schmitt-Very-Cool 851 98 435ms 26 Sep 2025 933rd inventshah 850 74 2ms 4 May 2022 933rd undersquire 850 74 2ms 24 Jun 2023 933rd rdmsr 850 74 2ms 24 Jun 2023 933rd Bmrl7 850 74 2ms 9 Jul 2023 933rd Vinterion 850 74 4ms 6 Nov 2023 933rd Herbert00709 🇵🇱 850 74 2ms 22 Dec 2023 939th krcs 🇵🇱 849 53 282ms 9 May 2022 939th ryanlanegit 849 53 260ms 19 Jun 2022 939th sisyphus-ppcg 🇦🇺 849 53 402ms 15 Aug 2022 942nd randolchance 849 63 11ms 8 Jan 2023 942nd CatsAreFluffy 849 63 10ms 18 Feb 2023 942nd amiralitaheri 849 63 10ms 23 Feb 2023 942nd RuyiLi 849 63 9ms 1 Apr 2023 942nd TaserTheFox 🇺🇸 849 63 10ms 25 May 2023 942nd pfysches-boop 849 63 9ms 6 Aug 2023 942nd mhgockel 849 63 10ms 19 Aug 2023 942nd NickTheEASDude 🇺🇸 849 63 10ms 18 Jan 2024 942nd 823126 849 63 14ms 14 Nov 2024 942nd Palladium02 849 63 9ms 12 May 2025 942nd 4very 849 63 10ms 10 Jun 2025 942nd Ultra814 849 63 9ms 21 Aug 2025 954th MeWhenI 🇻🇦 849 71 106ms 13 Dec 2022 955th frosster 849 80 11ms 4 days ago 956th DialFrost 🇸🇬 848 66 85ms 7 Apr 2025 956th KasperKivimaeki 🇫🇮 848 66 8ms 6 days ago 958th SirBogman 🇺🇸 848 89 38ms 4 May 2022 959th Shanethegamer 🇺🇸 848 98 119ms 26 Oct 2022 959th emgordon154 848 98 121ms 18 Feb 2025 First Prev 881–960 of 3,512 Next Last