The Calendar hole will go live in approximately 13 days. Why not try and solve it ahead of time?
ISBN in Python 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 157th Ripick 765 119 10ms 2 Feb 2023 157th Ythaenagor 765 119 10ms 5 Aug 2024 157th PyryL 🇫🇮 765 119 10ms 20 Aug 2024 157th JunkIce 765 119 9ms 25 Nov 2024 157th Stockoh 🇫🇷 765 119 9ms 13 Feb 2025 157th Alban-Boissard 765 119 10ms 14 Jun 2025 157th Flekay 🇩🇪 765 119 9ms 10 Jul 2025 168th fkantelberg 758 120 9ms 18 Jul 2023 168th Bmrl7 758 120 9ms 29 Feb 2024 168th elgan65536 758 120 16ms 1 Apr 2024 168th robin-scragg 758 120 10ms 25 Jul 2025 172nd Natanaelel 🇸🇪 752 121 9ms 12 Jan 2022 172nd NerdyMcNerd42 752 121 9ms 20 Aug 2022 172nd Kloppermand 🇩🇰 752 121 10ms 3 Oct 2022 172nd ehulinsky 🇺🇸 752 121 16ms 15 May 2023 172nd AbhilashaTandon 752 121 10ms 21 Sep 2023 172nd davecame 752 121 9ms 2 Oct 2023 172nd gussy420 752 121 9ms 23 Oct 2023 172nd tobyLovick 752 121 9ms 13 Dec 2023 180th jm600 746 122 9ms 19 Apr 2022 180th krcs 🇵🇱 746 122 10ms 29 Apr 2022 180th bbakersmith 746 122 10ms 6 Jun 2022 180th nstearns96 🇬🇧 746 122 10ms 29 Nov 2022 180th stertooy 🇧🇪 746 122 10ms 11 Jun 2024 180th croc54 746 122 11ms 8 Jan 2025 180th Matter1024 🇮🇳 746 122 9ms 15 Nov 2025 187th gitbedd 🇬🇧 740 123 10ms 10 Jan 2022 187th andre-lameirinhas 🇵🇹 740 123 9ms 8 Aug 2022 187th MaxElf999 740 123 10ms 13 Sep 2022 187th Mikey-Beep 🇬🇧 740 123 10ms 24 Aug 2023 187th bac0id 740 123 17ms 22 Sep 2023 187th HumanoidCPU 740 123 10ms 2 Mar 2025 187th Masttest 740 123 12ms 21 days ago 187th yujqiao 740 123 10ms 2 days ago 195th Ailko 🇧🇪 734 124 11ms 6 May 2022 195th qwjhvbxi 734 124 10ms 10 Feb 2024 195th leon-w 734 124 11ms 24 Jul 2024 195th jbjd 734 124 16ms 12 Sep 2024 195th smilesformiles3 734 124 10ms 14 Jun 2025 200th BenBanerjeeRichards 728 125 10ms 22 Apr 2022 200th richard-oelze 🇩🇪 728 125 9ms 8 May 2022 200th vishwathg 728 125 15ms 16 Sep 2022 200th Thonoton 728 125 16ms 24 Feb 2023 200th sandorstormen 728 125 16ms 11 Mar 2023 200th MiranDaniel 🇨🇿 728 125 16ms 28 Apr 2023 200th VictorStenvers 🇳🇱 728 125 17ms 26 Jun 2024 200th Terobero 728 125 16ms 3 Sep 2024 200th LostSyntax21 🇬🇧 728 125 16ms 9 Sep 2024 200th jamesthekee 728 125 10ms 22 Jan 2025 210th TobyBoyne 🇬🇧 722 126 11ms 28 Jan 2022 210th OllieBoyne 🇬🇧 722 126 10ms 2 Mar 2022 210th Anonymousellama21 722 126 10ms 14 Apr 2022 210th Trunksistor 🇫🇷 722 126 11ms 19 Apr 2022 210th docd 722 126 16ms 8 Aug 2022 210th LogicalJoe 722 126 16ms 4 May 2023 210th pde-bakk 🇳🇱 722 126 10ms 23 Oct 2023 210th mstang107 722 126 10ms 20 Dec 2023 210th DGipe 722 126 9ms 13 May 2024 210th retrohun 722 126 9ms 18 Oct 2024 210th yokasuretsu 722 126 9ms 23 Jan 2025 210th bknower 722 126 10ms 26 Jun 2025 222nd jacklynnepenick 717 127 9ms 15 Feb 2022 222nd Pena86 717 127 16ms 14 Sep 2022 222nd pascscha 717 127 9ms 18 Sep 2022 222nd DrPiranoid 717 127 10ms 8 Oct 2022 222nd QuincyNash 🇺🇸 717 127 9ms 13 Nov 2022 222nd epic-programmer-guy 717 127 10ms 21 Dec 2023 222nd AdamMorris377 717 127 9ms 29 Jul 2024 222nd 40fied4t 717 127 10ms 15 May 2025 222nd Luke44565 717 127 9ms 10 Aug 2025 222nd jacekwladzinski 717 127 9ms 5 Oct 2025 232nd gchenfc 711 128 9ms 24 Jan 2022 232nd pyrolitic 🇮🇪 711 128 11ms 5 Apr 2022 232nd hellwue 711 128 11ms 8 Feb 2023 232nd Wildst 711 128 11ms 4 Aug 2023 232nd sleepyStick 711 128 9ms 7 Dec 2023 232nd damoose717 711 128 10ms 23 May 2025 232nd RaBa21 🇭🇺 711 128 16ms 19 Jul 2025 239th amollberg 🇸🇪 705 129 10ms 21 Jan 2022 239th jfallon1997 705 129 10ms 18 Aug 2022 First Prev 161–240 of 364 Next Last
