The Calendar hole will go live in approximately 9 days. Why not try and solve it ahead of time?
Prime Numbers in C# 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 1st btnlq 1,000 53 342ms 10 Mar 2023 1st JayXon 🇺🇸 1,000 53 336ms 10 Mar 2023 1st Lydxn 🇨🇦 1,000 53 360ms 19 May 2023 1st AdrienHache 🇫🇷 1,000 53 329ms 20 Jun 2023 1st stefangimmillaro 1,000 53 339ms 15 Jul 2023 1st MeWhenI 🇻🇦 1,000 53 348ms 26 Jul 2023 1st namelessiw 1,000 53 375ms 12 Dec 2023 1st sean-niemann 🇺🇸 1,000 53 392ms 23 Dec 2024 1st Yax42 🇫🇷 1,000 53 376ms 9 Feb 2025 10th ScottHamper 981 54 302ms 21 Nov 2021 10th tomtheisen 🇺🇸 981 54 302ms 21 Nov 2021 12th fuzzylojik-golf 🇺🇸 841 63 384ms 31 Jul 2025 13th nwellnhof 🇩🇪 828 64 314ms 21 Dec 2021 13th WalrusesAreAwesome 828 64 378ms 11 Jan 2025 13th prplz 🇦🇺 828 64 343ms 23 Jan 2025 13th KasperKivimaeki 🇫🇮 828 64 352ms 3 hours ago 17th Attero 🇸🇪 815 65 317ms 21 Nov 2021 17th billings7 🇬🇧 815 65 321ms 21 Nov 2021 17th KatieLG 🇬🇧 815 65 384ms 21 Nov 2021 17th primo-ppcg 🇹🇭 815 65 321ms 21 Nov 2021 17th roavin 815 65 311ms 29 Jun 2022 17th annaproxy 815 65 340ms 19 May 2023 17th b-illy 🇬🇧 815 65 349ms 21 Jan 2025 24th Shanethegamer 🇺🇸 803 66 308ms 28 Dec 2021 24th Yewzir 🇧🇪 803 66 319ms 8 May 2023 24th janbehrens 🇩🇪 803 66 312ms 27 Nov 2023 24th SirBogman 🇺🇸 803 66 308ms 3 Jan 2024 28th SmartK8 🇨🇿 791 67 313ms 10 Oct 2022 29th KrausRaus 🇺🇸 779 68 329ms 26 Jun 2023 30th Gaddy 🇫🇷 768 69 330ms 1 Jun 2022 30th postie77 768 69 310ms 18 Apr 2023 32nd Irratix 🇳🇱 757 70 323ms 13 Dec 2021 32nd Ripick 757 70 314ms 18 Jul 2022 32nd CatsAreFluffy 757 70 330ms 28 Nov 2022 35th sultan 746 71 325ms 2 Apr 2024 36th tkr-sh 🇰🇵 736 72 307ms 4 May 2022 36th ChrisTheisen 736 72 328ms 19 Dec 2022 36th mathb0y512 736 72 316ms 8 Feb 2023 39th LS2021 726 73 319ms 24 Nov 2023 39th dokutan 726 73 356ms 14 Jul 2025 41st Meowsan91 🇨🇿 707 75 333ms 21 Nov 2021 42nd pan4ever 697 76 315ms 21 Nov 2021 42nd hamhub7 697 76 323ms 26 Aug 2022 42nd Matgc04 697 76 322ms 23 Feb 2024 42nd Squimbletin 697 76 349ms 22 Apr 2025 46th CarsonChr 🇺🇸 679 78 318ms 7 Apr 2024 47th hyvyys 671 79 320ms 21 Nov 2021 48th aliakseikalosha 663 80 383ms 21 Nov 2021 48th oren0 663 80 319ms 21 Nov 2021 48th adlerzei 663 80 347ms 5 May 2022 48th arctouch-sergeymetlov 663 80 322ms 21 Jun 2023 48th ElysiaVesper 663 80 317ms 19 Nov 2023 48th Re-Adventures 🇮🇳 663 80 372ms 15 Apr 2025 54th tdkkdt 🇷🇺 654 81 322ms 21 Nov 2021 54th tomh1012 654 81 385ms 21 Nov 2021 54th MLPdiscord 654 81 326ms 10 Jan 2022 54th josephdwalker 654 81 321ms 14 Nov 2023 58th ILMTitan 646 82 346ms 21 Nov 2021 58th Romain-1 🇫🇷 646 82 370ms 1 Jun 2022 58th arctouch-cristiannevianna 646 82 358ms 23 May 2023 58th kkoenig 646 82 318ms 25 Dec 2023 58th FreyLuis 646 82 347ms 17 Jan 2024 58th michelebastione 🇮🇹 646 82 384ms 27 Aug 2025 64th castur1 639 83 322ms 3 Feb 2022 65th JDiLenarda 🇫🇷 631 84 325ms 21 Nov 2021 65th najs91 631 84 319ms 21 Nov 2021 65th bac0id 631 84 320ms 22 Sep 2023 65th epic-programmer-guy 631 84 317ms 19 Dec 2023 65th QzLP2P 631 84 310ms 29 Mar 2024 65th malworthy 631 84 372ms 16 Aug 2024 65th arcpolaris 631 84 370ms 27 Mar 2025 72nd leth4 624 85 344ms 5 Jul 2023 72nd CaedenHarper 🇨🇦 624 85 379ms 17 Oct 2025 72nd Adix-null 🇱🇹 624 85 422ms 10 Nov 2025 75th ericlangedijk 🇸🇮 616 86 337ms 16 Mar 2022 75th Betuaredead 616 86 309ms 4 Jan 2023 75th HumanoidCPU 616 86 316ms 1 Apr 2024 78th pallbo 609 87 319ms 21 Nov 2021 78th Florian-Mt 609 87 354ms 14 Jul 2024 78th rifatx 609 87 359ms 19 Jul 2024 1–80 of 141 Next Last