The Calendar hole will go live in approximately 12 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 241st sisyphus-ppcg 🇦🇺 928 50 2,414ms 31 Jan 2023 241st saito-ta 🇯🇵 928 50 759ms 12 Dec 2024 243rd JayXon 🇺🇸 928 57 133ms 19 Aug 2024 244th sisyphus-ppcg 🇦🇺 928 65 106ms 22 hours ago 244th ovs-code 🇩🇪 928 65 123ms 12 hours ago 246th roavin 927 84 337ms 23 Jun 2022 246th tkr-sh 🇰🇵 927 84 318ms 20 Aug 2022 246th Nickmiste 927 84 326ms 9 Nov 2022 246th Matgc04 927 84 347ms 19 May 2023 246th postie77 927 84 323ms 19 May 2023 246th ertz1ertz 927 84 330ms 13 Sep 2024 246th Grabnukebomb 927 84 351ms 13 Sep 2024 246th Shanethegamer 🇺🇸 927 84 365ms 9 Apr 2025 246th HumanoidCPU 927 84 392ms 10 Apr 2025 246th annaproxy 927 84 371ms 11 Apr 2025 246th Re-Adventures 🇮🇳 927 84 376ms 15 Apr 2025 246th janbehrens 🇩🇪 927 84 372ms 17 Apr 2025 246th Flix7dev 🇧🇪 927 84 384ms 21 Oct 2025 259th h3ra993huskp 🇯🇵 927 90 440ms 19 days ago 260th KasperKivimaeki 🇫🇮 927 104 237ms 8 days ago 261st edsrzf 🇳🇿 925 54 817ms 13 Sep 2025 261st CaedenHarper 🇨🇦 925 54 826ms 27 Sep 2025 261st sean-niemann 🇺🇸 925 54 833ms 27 Sep 2025 261st albanian-laundromat 925 54 859ms 14 Nov 2025 261st xsot 🇸🇬 925 54 873ms 15 Nov 2025 266th btnlq 924 59 6ms 6 Nov 2022 267th Lydxn 🇨🇦 924 90 125ms 6 May 2022 268th Bubbler-4 923 33 2,528ms 6 May 2022 268th rak1507 🇬🇧 923 33 108ms 8 May 2022 268th ngn 🇧🇬 923 33 25ms 11 May 2022 268th zacjl 923 33 32ms 3 Jun 2025 268th GrayJoKing 🇦🇺 923 33 13ms 4 Jun 2025 268th HPWiz 🇳🇿 923 33 9ms 16 Nov 2025 274th nwellnhof 🇩🇪 923 51 43ms 4 May 2022 274th primo-ppcg 🇹🇭 923 51 41ms 6 May 2022 274th janlelis 923 51 44ms 10 May 2022 274th Natanaelel 🇸🇪 923 51 58ms 2 Jun 2022 278th uiamn 923 58 11ms 6 Sep 2022 278th 5quiwyrm 923 58 10ms 29 Sep 2022 278th alasdair-greenland 923 58 10ms 13 Jan 2023 278th kirjavascript 923 58 10ms 4 Aug 2025 278th Posandu 923 58 10ms 26 Aug 2025 278th mrxz 🇳🇱 923 58 11ms 3 Sep 2025 284th MichalMarsalek 🇨🇿 923 71 143ms 5 May 2022 284th Lydxn 🇨🇦 923 71 174ms 7 May 2022 284th GrayJoKing 🇦🇺 923 71 122ms 8 May 2022 284th JayXon 🇺🇸 923 71 121ms 8 May 2022 284th Steffan153 🇫🇮 923 71 133ms 9 Mar 2023 284th Shanethegamer 🇺🇸 923 71 131ms 15 May 2023 284th MeWhenI 🇻🇦 923 71 128ms 8 Aug 2023 284th sean-niemann 🇺🇸 923 71 127ms 9 Jan 2025 292nd Steffan153 🇫🇮 922 76 11ms 15 May 2023 292nd primo-ppcg 🇹🇭 922 76 17ms 15 May 2023 292nd Lydxn 🇨🇦 922 76 8ms 22 May 2023 292nd GrayJoKing 🇦🇺 922 76 13ms 24 Aug 2023 296th Herbert00709 🇵🇱 922 92 85ms 17 Nov 2023 296th 4QT0R 922 92 60ms 23 Nov 2023 296th ovs-code 🇩🇪 922 92 76ms 3 Jun 2024 299th xnor-gate 920 63 187ms 20 Jan 2025 300th pardouin 🇫🇷 919 72 3,684ms 21 May 2025 301st primo-ppcg 🇹🇭 918 61 6ms 6 May 2022 301st sisyphus-ppcg 🇦🇺 918 61 9ms 14 Jul 2022 303rd Lydxn 🇨🇦 918 70 96ms 7 May 2022 303rd JayXon 🇺🇸 918 70 96ms 7 May 2022 305th JayXon 🇺🇸 918 79 570ms 5 Apr 2023 305th Lydxn 🇨🇦 918 79 543ms 9 Apr 2023 307th JayXon 🇺🇸 918 105 246ms 4 Oct 2025 308th Steffan153 🇫🇮 917 71 98ms 14 Oct 2022 308th Shanethegamer 🇺🇸 917 71 100ms 15 Oct 2022 308th stefangimmillaro 917 71 100ms 16 Oct 2022 308th MeWhenI 🇻🇦 917 71 100ms 16 Oct 2022 308th Steffan153 🇫🇮 917 71 4ms 10 Dec 2022 308th synt7x 🇺🇸 917 71 4ms 7 Jul 2025 314th annaproxy 917 79 111ms 24 Aug 2022 314th GrayJoKing 🇦🇺 917 79 83ms 28 Aug 2022 314th IanUtley 917 79 114ms 3 Nov 2023 314th Kacarott 🇦🇺 917 79 117ms 13 Jun 2024 318th Steffan153 🇫🇮 917 81 24ms 11 Dec 2023 319th arctouch-cristiannevianna 916 85 341ms 3 Apr 2023 319th tomtheisen 🇺🇸 916 85 396ms 10 Apr 2025 First Prev 241–320 of 3,526 Next Last