The Calendar hole will go live in approximately 9 days. Why not try and solve it ahead of time?
All holes in C# 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 Holes Points Bytes Submitted 801st sylvain69780 1 631 683 20 Nov 2023 802nd RobertTheBastian 1 627 118 21 Nov 2021 802nd Snidden 1 627 118 21 Nov 2021 802nd StefanoFiumara 1 627 118 21 Nov 2021 805th YourSenseiCreeper 2 623 569 2 Dec 2023 806th lilyyy411 1 622 82 21 Nov 2021 807th testtagg 1 622 119 21 Nov 2021 807th bwenstar 1 622 119 11 Aug 2022 807th SebiPanther 1 622 119 12 Nov 2022 810th MHunter-NZ 🇳🇿 1 621 140 21 Nov 2021 811th MadScience137 1 620 100 12 Oct 2022 812th 00anwi 1 619 118 4 Dec 2022 813th AllisonTowers 1 617 120 13 Apr 2022 814th PaulMWeiser 1 614 88 27 Feb 2023 815th lawnboyy 1 614 342 21 Nov 2021 816th louisbosqui 1 612 121 21 Nov 2021 816th salcosser 1 612 121 25 Aug 2023 818th Lizard314 1 600 85 21 Nov 2021 819th nakatchi 1 596 104 17 Mar 2024 820th arctouch-nilobasilio 1 592 125 9 Nov 2022 821st GulgDev 1 592 147 22 Mar 2023 822nd emmertgergo 1 591 132 27 Apr 2023 823rd louisoftokyo 2 590 1,106 13 Oct 2025 824th Narik1 1 588 216 3 Apr 2023 825th Rambso 1 586 87 28 Mar 2025 826th FEZfan 🇦🇺 1 583 127 27 May 2025 827th PotatoSaladOverlord 1 578 128 19 Jan 2024 828th mihaits 1 573 89 21 Nov 2021 829th AustinBratcher 1 573 96 10 Nov 2023 830th jacobly0 🇺🇸 2 572 2,020 15 Aug 2023 831st Arasfon 1 569 130 21 Nov 2021 832nd Jvardas 1 565 154 21 Nov 2021 833rd Mituzsuki 2 564 1,216 21 Nov 2021 834th nnawalage 1 557 377 21 Nov 2021 835th ian-h-chamberlain 🇺🇸 1 556 99 21 Nov 2021 836th dlorddd 1 556 126 21 Nov 2021 836th orifu 1 556 126 29 Oct 2024 838th oschmidh 1 548 93 21 Nov 2021 838th sech1p 🇵🇱 1 548 93 21 Nov 2021 840th spektumus 1 544 136 21 Nov 2021 840th ctwolfe96 1 544 136 13 Jun 2022 842nd RockOfStone 1 543 94 23 Mar 2024 843rd paulbechard 1 543 208 18 Sep 2022 844th 2022dyx 1 542 144 13 Jul 2024 845th Rhinozz 🇨🇦 1 541 135 21 Nov 2021 846th Elf-Lord-Games 1 540 161 26 Sep 2022 847th isorlab49 1 538 145 21 Apr 2023 848th 1isaaclaryea 1 536 138 21 Nov 2021 849th JarrinseCubillo 3 534 6,177 21 Nov 2025 850th j-Ewan 1 532 139 9 Feb 2022 850th gurglemurgle5 1 532 139 25 Mar 2022 852nd tobiasberei 1 532 154 6 Apr 2023 853rd cingulataluke 1 531 96 2 Jun 2024 854th jnuntha-mednet 1 529 140 21 Feb 2023 855th johnstrand 1 524 166 11 May 2020 856th JayantaNath 1 519 104 15 Apr 2022 857th kallerdaller 1 515 408 2 Sep 2022 858th volpi-m 🇫🇷 1 514 144 21 Nov 2021 858th jspa2 1 514 144 2 Nov 2022 858th neonchickens 1 514 144 10 Nov 2023 861st Robbe7730 1 510 100 21 Nov 2021 862nd abailey2020 🇺🇸 2 509 1,203 21 Nov 2021 863rd uncertaain 1 505 101 28 Dec 2023 864th Joe85gr 1 497 175 30 Sep 2023 865th prestosilver 🇺🇸 1 497 553 18 days ago 866th xk0fe 1 496 423 5 Mar 2025 867th zenstain 1 493 150 14 Jul 2022 868th Fmbalbuena 1 490 149 21 Nov 2021 869th xkacer 🇨🇿 1 486 111 21 Nov 2021 869th anter69 🇭🇺 1 486 111 18 Sep 2024 871st NovemberOrWhatever 1 477 107 6 Nov 2022 872nd sushicombo 1 477 155 21 Nov 2021 872nd mervynriandy 1 477 155 21 Nov 2021 874th christensendaniel 2 476 1,246 14 May 2024 875th mikesuffield 1 475 183 10 Dec 2021 876th xDavidL 1 474 192 19 Feb 2022 877th michael-pruglo 🇺🇦 1 471 155 6 Jul 2022 877th 4hg 🇺🇸 1 471 155 9 Nov 2022 877th LostSyntax21 🇬🇧 1 471 155 24 Nov 2024 880th nac5604 1 471 157 21 Nov 2021 First Prev 801–880 of 1,020 Next Last