The Calendar hole will go live in approximately 13 days. Why not try and solve it ahead of time?
Card Number Validation in all languages 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 719th kistlerf 🇨🇭 452 143 18ms 19 May 2025 722nd dokutan 451 63 3ms 26 Nov 2024 723rd snoozingnewt 🇨🇦 451 176 1ms 2 Nov 2025 724th varhammer 🇷🇺 450 223 11ms 23 Feb 2025 725th hiichbindermax 449 144 15ms 2 Oct 2024 725th mathisfun271 449 144 9ms 14 Oct 2024 725th bob-th 449 144 10ms 22 Oct 2024 728th dokutan 445 109 10ms 19 Oct 2024 729th Flekay 🇩🇪 445 145 10ms 10 Jul 2025 730th grey0ut 444 105 425ms 11 Jan 2025 731st croc54 442 146 12ms 15 Dec 2024 732nd MyXoToD 🇩🇪 441 146 9ms 26 May 2025 733rd Yewzir 🇧🇪 440 171 12ms 26 Dec 2024 734th PyryL 🇫🇮 439 147 10ms 1 Mar 2025 735th mbittner20 436 148 11ms 13 Oct 2024 735th YAJUE114514 436 148 10ms 6 days ago 737th Andrey2001 435 132 720ms 21 days ago 738th JOrE20 🇺🇸 434 136 754ms 11 days ago 739th psaban 434 149 16ms 31 Jul 2025 739th TheZwierzLF 🇵🇱 434 149 11ms 23 days ago 741st KatieLG 🇬🇧 433 183 1ms 2 Oct 2025 742nd dokutan 432 130 401ms 17 Oct 2024 743rd Mabeloid 🇳🇴 432 133 538ms 2 Oct 2024 744th KatieLG 🇬🇧 431 108 6ms 13 Oct 2024 745th jameswmccarty 431 150 10ms 5 Oct 2024 745th yousefalizadeh 431 150 10ms 23 Oct 2024 745th feherd 431 150 10ms 31 Oct 2024 745th kadamkaustubh 431 150 9ms 8 Nov 2025 749th snoozingnewt 🇨🇦 430 111 41ms 2 Nov 2025 750th snoozingnewt 🇨🇦 427 267 28ms 4 hours ago 751st adamnielson42 🇺🇸 425 152 12ms 6 Oct 2024 751st voidgloom 425 152 10ms 22 Oct 2024 751st omero-san 425 152 9ms 22 Sep 2025 751st brochmann 🇸🇪 425 152 13ms 12 Oct 2025 755th MeWhenI 🇻🇦 424 143 6ms 2 Oct 2024 756th denisfouchard 422 153 10ms 21 Aug 2025 757th osNiko 🇧🇷 419 154 11ms 21 Aug 2025 758th celiendonze 🇨🇭 417 155 11ms 17 Oct 2025 759th Arkadios200 417 196 98ms 21 Oct 2025 760th Shotokhan 414 156 9ms 21 Sep 2025 761st lhulinsky 411 157 9ms 21 Oct 2024 762nd ThatAlo 409 158 10ms 9 Dec 2024 763rd webmiche 406 159 10ms 3 Nov 2025 764th dieggsy 406 247 18ms 10 Oct 2024 765th Mabeloid 🇳🇴 405 159 9ms 12 Oct 2024 766th CheeseCake628 🇳🇴 404 160 102ms 5 Nov 2024 767th snoozingnewt 🇨🇦 404 223 75ms 2 Nov 2025 768th pres-abhisheksinha 401 161 10ms 8 Oct 2024 769th ibixina 399 162 9ms 13 Oct 2024 769th TheAtrossian 399 162 10ms 5 Jan 2025 771st aksyristos 399 172 2ms 25 days ago 772nd Ralac07 🇦🇺 397 162 11ms 3 Oct 2024 773rd Maximizer02 396 201 10ms 1 Oct 2024 774th snoozingnewt 🇨🇦 392 276 40ms 12 days ago 775th Vaekor 391 165 10ms 15 Dec 2024 776th ehulinsky 🇺🇸 384 158 5ms 2 Apr 2025 777th fischfood 384 176 4ms 22 Oct 2024 778th JesseNoEyes 🇺🇸 382 169 10ms 1 Oct 2024 779th CheeseCake628 🇳🇴 381 151 426ms 18 Oct 2025 780th zyc-2024 🇨🇳 380 170 9ms 5 Oct 2024 781st ComputerKWasTaken 🇺🇸 378 171 10ms 14 Oct 2024 782nd snoozingnewt 🇨🇦 376 267 13ms 2 Nov 2025 783rd KatieLG 🇬🇧 375 218 108ms 26 days ago 784th navier-1 373 173 11ms 22 Sep 2025 785th c0d3-4-F00d 🇩🇪 373 184 2ms 9 Jan 2025 786th RobGLambert 372 232 1,062ms 8 Jun 2025 787th snoozingnewt 🇨🇦 372 313 40ms 2 Nov 2025 788th RedzGoose 🇦🇺 369 187 101ms 2 Oct 2024 789th P1nk-P0nk 369 215 3ms 18 Oct 2024 790th clayboll99 367 176 10ms 10 Jul 2025 791st Upload-and-View 🇺🇦 365 177 17ms 9 Aug 2025 792nd OSYCh314 🇦🇺 363 178 10ms 2 Nov 2024 793rd calum12345 359 180 10ms 26 Mar 2025 794th zt14427 355 182 10ms 27 Dec 2024 795th The-Wolfson 355 230 100ms 16 Dec 2024 796th JOrE20 🇺🇸 354 208 120ms 11 days ago 797th IoLimmer 353 183 9ms 10 Oct 2024 798th aksyristos 351 184 16ms 15 Nov 2024 799th sciencejiho 348 197 2ms 11 Feb 2025 800th estomagordo 🇳🇱 347 186 10ms 15 Jul 2025 First Prev 721–800 of 847 Next Last