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 321st ridingqwerty 🇺🇸 619 147 10ms 26 Dec 2023 322nd Tkidder132 615 148 11ms 28 Aug 2023 323rd KevinLyvers 611 149 10ms 17 Dec 2022 324th alytarik 603 151 9ms 11 Jan 2022 324th AnnoyedArt1256 603 151 16ms 3 Jul 2025 326th rafaga 599 152 9ms 8 Aug 2022 327th GeneralFabian 595 153 16ms 14 Dec 2024 327th PotatoSaladOverlord 595 153 16ms 20 Jun 2025 329th jmath3912 591 154 10ms 23 Jul 2022 330th Lemonz-13223 583 156 9ms 18 Oct 2022 330th eddvrs 583 156 10ms 22 Dec 2023 330th NoneTheFewer 583 156 15ms 18 May 2024 333rd lovernj 580 157 16ms 7 Feb 2022 333rd ellygaytor 580 157 10ms 28 Feb 2022 333rd amanda-j-brown 580 157 9ms 2 Nov 2023 336th Bananapants22 576 158 9ms 2 Sep 2022 336th alfonsoalves 576 158 10ms 29 Feb 2024 338th bthalheim 569 160 9ms 3 Sep 2022 339th SheepIsGoat 565 161 10ms 19 Jan 2023 339th 123mjb 565 161 18ms 19 Nov 2025 341st zwxzwxzwx21 562 162 10ms 15 Jan 2024 341st mikehanus 562 162 10ms 29 Jan 2024 343rd hymanimy 542 168 10ms 1 Apr 2022 344th DrPrettyman 538 169 15ms 6 Jul 2023 345th arnimattr 532 171 9ms 23 Jun 2023 346th jameswmccarty 523 174 16ms 10 Jul 2024 347th cseiter 520 175 10ms 21 Jun 2022 348th 4ndyJ 🇬🇧 514 177 10ms 15 Feb 2023 349th kevinnaviapaiva 506 180 9ms 12 Feb 2025 350th vgamula 🇺🇦 503 181 11ms 31 Oct 2023 351st atazzam 🇺🇸 495 184 9ms 28 Mar 2022 352nd te-chnical 479 190 82ms 4 May 2025 353rd sciencejiho 464 196 10ms 9 Apr 2024 354th dylanjones92 423 215 10ms 18 Jan 2024 354th Florian-Mt 423 215 15ms 9 Jul 2024 356th justpic1 416 219 10ms 30 Mar 2023 357th Zhenyu-Bo 397 229 11ms 31 Jul 2025 358th felixcroc 384 237 9ms 28 Mar 2023 359th KatieLG-Transpiler 🇬🇧 371 245 9ms 25 Jun 2022 360th joshuamkite 360 253 10ms 23 Aug 2023 361st fl3ur1nestimable 358 254 11ms 3 Apr 2022 362nd creeperoutcast1 350 260 11ms 20 Sep 2023 363rd Upload-and-View 🇺🇦 316 288 11ms 17 Aug 2025 364th AidanWalter 103 884 10ms 1 Jan 2025 First Prev 321–364 of 364
