The Calendar hole will go live in approximately 13 days. Why not try and solve it ahead of time?
ISBN 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 80th Seek64 🇩🇪 717 99 10ms 24 Sep 2024 80th jared-hughes 717 99 9ms 18 days ago 83rd xsot 🇸🇬 710 100 12ms 21 Jul 2023 83rd inventshah 710 100 10ms 3 Aug 2023 83rd StefanHabel 🇨🇦 710 100 9ms 5 Sep 2023 83rd MeWhenI 🇻🇦 710 100 10ms 7 Dec 2023 83rd lynn 710 100 9ms 21 Jun 2024 83rd ryyyn 🇺🇸 710 100 14ms 28 Oct 2025 83rd CaedenHarper 🇨🇦 710 100 10ms 18 days ago 90th 0e4ef622 703 101 11ms 21 Jun 2022 90th bricknellj 703 101 10ms 22 Jun 2024 92nd b10011 🇫🇮 696 102 9ms 14 Jan 2023 92nd zacjl 696 102 10ms 21 Oct 2023 92nd bzijlema 🇳🇱 696 102 9ms 15 Oct 2024 92nd moustave 696 102 10ms 25 Jun 2025 92nd blaztoma 🇱🇹 696 102 9ms 9 Oct 2025 97th janbehrens 🇩🇪 689 103 9ms 23 Jun 2023 97th orthoplex 🇨🇽 689 103 10ms 25 Nov 2023 97th abc7-12 689 103 9ms 26 Jun 2024 97th madex 🇩🇪 689 103 10ms 7 Aug 2025 97th Lv0Sys 🇵🇱 689 103 10ms 12 days ago 97th FortuiteMan 🇫🇷 689 103 11ms 10 hours ago 103rd VictorFordham 683 104 10ms 20 Feb 2023 103rd Alex-x90 🇺🇸 683 104 9ms 3 Aug 2023 103rd mathisfun271 683 104 10ms 5 Feb 2024 103rd EnTerr 683 104 9ms 8 Sep 2024 103rd KasperKivimaeki 🇫🇮 683 104 10ms 11 Jul 2025 108th Bonjour27891 🇻🇳 676 105 18ms 15 Jul 2022 108th stefangimmillaro 676 105 10ms 26 Dec 2022 108th betaveros 676 105 10ms 1 Jan 2023 108th 5cw 🇺🇸 676 105 9ms 3 May 2023 108th minhtrancccp 676 105 9ms 26 Sep 2023 108th Emutis 🇱🇹 676 105 9ms 4 Feb 2025 114th Bulmenisaurus 670 106 10ms 2 Feb 2025 115th fourth-bit 664 107 9ms 10 Jul 2024 115th fuzzylojik-golf 🇺🇸 664 107 10ms 19 May 2025 115th solisolu 664 107 10ms 23 days ago 118th prplz 🇦🇺 657 108 10ms 11 Jan 2022 118th galloj 🇨🇿 657 108 10ms 21 Sep 2022 118th TaserTheFox 🇺🇸 657 108 9ms 3 Apr 2023 118th cros107 🇦🇺 657 108 10ms 10 Aug 2025 122nd cefqrn 651 109 9ms 24 Dec 2022 122nd AlexanderFair 651 109 10ms 11 Jul 2023 122nd firegene 🇮🇪 651 109 10ms 18 Jan 2024 122nd andrewjc2000 651 109 10ms 9 Mar 2025 126th sultan 645 110 9ms 24 Feb 2024 126th fgrosshans 🇫🇷 645 110 10ms 16 Jul 2024 126th edsrzf 🇳🇿 645 110 9ms 30 Jul 2025 126th InigoK 🇺🇸 645 110 10ms 22 Sep 2025 126th vhoulbreque 🇫🇷 645 110 11ms 23 days ago 131st neihousaigaai 640 111 11ms 11 Jan 2022 131st knutae 🇳🇴 640 111 10ms 18 Jan 2022 131st rschwa6308 🇺🇸 640 111 9ms 22 Mar 2023 131st zbreit 🇺🇸 640 111 11ms 22 Mar 2023 131st BREMAUCY 🇫🇷 640 111 10ms 15 Apr 2025 131st now4est 🇯🇵 640 111 9ms 25 Sep 2025 137th guilhem-roy 🇫🇷 634 112 9ms 5 Jun 2022 137th ahmetdemirag 🇨🇾 634 112 9ms 30 Jun 2024 137th CommandLeo 🇮🇹 634 112 10ms 3 Nov 2025 140th commandblockguy 🇺🇸 628 113 11ms 3 Nov 2022 140th davitf 628 113 9ms 30 Apr 2024 140th kbeat 🇰🇿 628 113 12ms 18 May 2025 143rd aonkeeper4 623 114 9ms 5 Jul 2022 143rd thienudomsrirungruang 623 114 16ms 14 May 2024 143rd jtaxen 623 114 10ms 8 Jun 2024 143rd CutSandstone 623 114 9ms 8 Jul 2024 147th PiterAnnema 617 115 16ms 23 Mar 2022 147th AGoyet 617 115 9ms 29 Jun 2022 147th Eilonlif 🇮🇱 617 115 10ms 11 Sep 2022 147th IsmaelGSerrano 617 115 10ms 2 Nov 2022 147th bobbysq 617 115 9ms 22 Jan 2023 147th msbranicky 617 115 9ms 25 Jul 2023 147th ArenaGrenade 617 115 10ms 19 Feb 2024 147th NickTheEASDude 🇺🇸 617 115 10ms 15 May 2024 147th maxgodfrey2004 🇨🇦 617 115 10ms 8 Jan 2025 147th Pyroan 617 115 9ms 21 Feb 2025 147th chartung17 617 115 10ms 24 Mar 2025 158th martinnorling 🇸🇪 612 116 10ms 18 Feb 2022 158th Indivicivet 612 116 10ms 9 May 2022 158th MichalMarsalek 🇨🇿 612 116 10ms 30 Nov 2022 First Prev 81–160 of 364 Next Last