The Calendar hole will go live in approximately 10 days. Why not try and solve it ahead of time?
Collatz in Python in chars. 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 Chars Time Submitted 75th JunkIce 905 63 23ms 24 Nov 2024 75th Kowalskiexe 🇵🇱 905 63 19ms 19 Apr 2025 75th 123mjb 905 63 23ms 2 Jun 2025 75th DrakeSeteraO 905 63 52ms 24 Oct 2025 75th enigma 905 63 40ms 2 hours ago 86th NerdyMcNerd42 891 64 19ms 26 Oct 2022 86th tpasfieldERAU 891 64 23ms 14 Nov 2022 86th CheeseCake628 🇳🇴 891 64 22ms 6 Jan 2023 86th adamnielson42 🇺🇸 891 64 19ms 25 Apr 2023 86th nathsou 🇫🇷 891 64 19ms 2 Sep 2023 86th zwxzwxzwx21 891 64 25ms 30 Jan 2024 86th steffan-polygolf 891 64 19ms 8 Mar 2024 86th Jacob385 891 64 57ms 4 Apr 2024 86th gallium-gonzollium 891 64 28ms 26 Aug 2024 95th yzhs 🇩🇪 877 65 19ms 16 Jun 2022 95th rollershutter 877 65 20ms 9 Sep 2022 95th bac0id 877 65 20ms 26 Sep 2023 95th robin-scragg 877 65 23ms 8 Jun 2025 95th RaBa21 🇭🇺 877 65 29ms 11 Jul 2025 95th TransformLikeATensor 877 65 20ms 17 Oct 2025 101st moustave 851 67 23ms 7 Nov 2024 102nd Bubbler-4 838 68 15ms 15 Nov 2022 102nd neel11235813 838 68 23ms 31 Dec 2022 102nd Rubiksmath 838 68 14ms 14 Aug 2023 102nd SB-945 838 68 23ms 7 Feb 2024 106th nwellnhof 🇩🇪 826 69 22ms 4 May 2022 106th GolfingSuccess 🇬🇷 826 69 15ms 5 May 2022 106th jared-hughes 826 69 17ms 5 May 2022 106th sisyphus-ppcg 🇦🇺 826 69 14ms 6 May 2022 106th lynn 826 69 16ms 22 Aug 2022 106th AlexanderFair 826 69 23ms 19 Jul 2023 106th AlephSquirrel 826 69 478ms 30 Dec 2023 106th davecame 826 69 22ms 20 Aug 2024 106th salvatore-abello 826 69 21ms 5 Sep 2024 106th zacjl 826 69 17ms 19 Sep 2024 106th kops-cg 826 69 22ms 9 Feb 2025 106th 4atj 826 69 3,539ms 30 Jun 2025 106th dirckvdende 826 69 18ms 11 Jul 2025 106th xnor-gate 826 69 16ms 19 Aug 2025 106th BrunoVisnadi 🇧🇷 826 69 16ms 1 Oct 2025 106th bizy-coder 826 69 16ms 21 Nov 2025 106th bricknellj 826 69 17ms 16 days ago 123rd MichalMarsalek 🇨🇿 814 70 19ms 5 May 2022 123rd primo-ppcg 🇹🇭 814 70 23ms 5 May 2022 123rd prplz 🇦🇺 814 70 18ms 5 May 2022 123rd rak1507 🇬🇧 814 70 19ms 7 May 2022 123rd inventshah 814 70 17ms 9 May 2022 123rd k3w1k0d3r 814 70 18ms 22 Jun 2022 123rd Bonjour27891 🇻🇳 814 70 20ms 14 Jul 2022 123rd OllieBoyne 🇬🇧 814 70 18ms 19 Jul 2022 123rd wen1now 814 70 19ms 8 Aug 2022 123rd 051 🇸🇬 814 70 18ms 8 Aug 2022 123rd Sp3000 🇦🇺 814 70 19ms 8 Aug 2022 123rd betaveros 814 70 19ms 9 Aug 2022 123rd shelerr 814 70 18ms 9 Sep 2022 123rd stewSquared 🇺🇸 814 70 22ms 27 Sep 2022 123rd myfatemi04 814 70 19ms 4 Nov 2022 123rd kevinmchung 814 70 18ms 4 Nov 2022 123rd fourth-bit 814 70 18ms 29 Nov 2022 123rd aksyristos 814 70 18ms 25 Dec 2022 123rd thizanne 814 70 20ms 27 Dec 2022 123rd stefangimmillaro 814 70 19ms 6 Feb 2023 123rd Seek64 🇩🇪 814 70 18ms 7 Feb 2023 123rd FieryIceStickie 814 70 19ms 3 Apr 2023 123rd MeWhenI 🇻🇦 814 70 19ms 30 Apr 2023 123rd kellantech 814 70 23ms 15 May 2023 123rd InigoK 🇺🇸 814 70 19ms 14 Jun 2023 123rd quimey 814 70 15ms 15 Jun 2023 123rd janbehrens 🇩🇪 814 70 19ms 24 Nov 2023 123rd namelessiw 814 70 20ms 9 Jan 2024 123rd mathisfun271 814 70 18ms 13 Feb 2024 123rd ThijsLuttikhuis 814 70 19ms 3 Mar 2024 123rd jtaxen 814 70 18ms 1 Apr 2024 123rd abc7-12 814 70 18ms 6 May 2024 123rd ahmetdemirag 🇨🇾 814 70 18ms 9 Jun 2024 123rd FranklinJiaChen 814 70 21ms 4 Jul 2024 123rd 5cw 🇺🇸 814 70 18ms 13 Jul 2024 123rd lgrandco 814 70 19ms 9 Oct 2024 123rd snydej 814 70 19ms 21 Nov 2024 123rd erikji 814 70 19ms 4 Feb 2025 First Prev 81–160 of 812 Next Last