The Calendar hole will go live in approximately 5 days. Why not try and solve it ahead of time?
Evil Numbers in Ruby 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 1st Lydxn 🇨🇦 1,000 27 36ms 4 Feb 2022 1st radarek 🇵🇱 1,000 27 37ms 25 Mar 2022 1st pardouin 🇫🇷 1,000 27 37ms 2 Sep 2025 4th janlelis 964 28 37ms 5 Jan 2020 4th primo-ppcg 🇹🇭 964 28 34ms 5 Oct 2020 4th JayXon 🇺🇸 964 28 38ms 28 Feb 2021 4th sisyphus-ppcg 🇦🇺 964 28 37ms 10 Jun 2021 4th nwellnhof 🇩🇪 964 28 34ms 1 Nov 2021 4th lynn 964 28 36ms 4 Feb 2022 4th OhmNomNom 964 28 33ms 30 Oct 2022 4th Steffan153 🇫🇮 964 28 40ms 17 Feb 2023 4th Shanethegamer 🇺🇸 964 28 36ms 22 Mar 2023 4th xsot 🇸🇬 964 28 40ms 25 May 2023 4th stefangimmillaro 964 28 36ms 4 Aug 2023 4th MeWhenI 🇻🇦 964 28 34ms 4 Aug 2023 4th Natanaelel 🇸🇪 964 28 43ms 14 Mar 2024 4th ovs-code 🇩🇪 964 28 39ms 22 Apr 2024 4th sean-niemann 🇺🇸 964 28 42ms 27 Dec 2024 4th fuzzylojik-golf 🇺🇸 964 28 35ms 29 Aug 2025 20th JOrE20 🇺🇸 931 29 34ms 6 hours ago 21st FlyingPenguin223 871 31 36ms 1 Nov 2024 22nd prplz 🇦🇺 844 32 34ms 16 Mar 2020 22nd GrayJoKing 🇦🇺 844 32 36ms 25 Jan 2021 22nd emgordon154 844 32 35ms 21 Sep 2024 25th jaredcrystal 🇺🇸 818 33 37ms 10 Dec 2018 25th yzhs 🇩🇪 818 33 45ms 8 Sep 2020 25th Waffle3z 818 33 48ms 11 Jan 2021 25th razetime 818 33 36ms 25 Jan 2021 25th rak1507 🇬🇧 818 33 34ms 25 Jan 2021 25th rbviz 818 33 36ms 29 Mar 2021 25th 4hg 🇺🇸 818 33 42ms 6 Jul 2022 25th m-tkach 🇺🇦 818 33 35ms 9 May 2023 25th CaedenHarper 🇨🇦 818 33 38ms 28 Aug 2025 25th blaztoma 🇱🇹 818 33 51ms 13 Nov 2025 35th j55d 794 34 39ms 3 Dec 2017 35th SirBogman 🇺🇸 794 34 35ms 14 Feb 2020 35th janbehrens 🇩🇪 794 34 38ms 24 Mar 2021 35th hugolgst 794 34 36ms 4 Jun 2021 35th anter69 🇭🇺 794 34 42ms 27 Jun 2021 35th Marin-Kitagawa 794 34 35ms 18 Jul 2021 35th olivermrose 🇺🇸 794 34 37ms 27 Aug 2021 35th o0lit3 🇺🇸 794 34 37ms 11 Sep 2021 35th UladzimirSukharukau 794 34 37ms 13 Sep 2021 35th KatieLG 🇬🇧 794 34 38ms 1 Oct 2021 35th akshatj27 🇦🇶 794 34 36ms 11 Jan 2022 35th Irratix 🇳🇱 794 34 41ms 4 Mar 2022 35th orthoplex 🇨🇽 794 34 35ms 1 Apr 2022 35th Mortis66666 794 34 35ms 14 Jul 2022 35th jared-hughes 794 34 36ms 9 Sep 2022 35th Andriamanitra 🇫🇮 794 34 42ms 22 Sep 2022 35th DialFrost 🇸🇬 794 34 37ms 29 Jan 2023 35th Yewzir 🇧🇪 794 34 39ms 17 Nov 2023 35th dokutan 794 34 35ms 17 Jul 2025 54th hrrs01 771 35 39ms 14 Mar 2020 54th proton 🇩🇪 771 35 34ms 9 Jun 2020 54th hiddicop 🇸🇪 771 35 36ms 29 Jan 2021 54th liemvo 🇻🇳 771 35 34ms 16 Apr 2021 54th ls-samer-abuthaher 771 35 38ms 7 Oct 2022 54th muraterogl 🇹🇷 771 35 33ms 31 Dec 2022 54th beirigo 🇧🇷 771 35 37ms 21 Nov 2025 61st vonagam 750 36 41ms 8 Nov 2017 61st sk- 750 36 36ms 12 Sep 2019 61st gilufin 750 36 38ms 23 May 2021 61st daninnm 750 36 37ms 23 Jul 2021 61st jbbarth 🇫🇷 750 36 41ms 21 Aug 2021 61st annaproxy 750 36 39ms 24 Aug 2022 67th jimworm 730 37 38ms 8 Nov 2017 67th acornellier 730 37 39ms 1 Dec 2021 67th pilaf 🇦🇷 730 37 38ms 14 Apr 2022 67th Haksell 🇦🇶 730 37 36ms 22 Feb 2023 67th rniii 730 37 37ms 21 Aug 2023 67th aaronze 🇦🇺 730 37 39ms 17 Sep 2023 67th olleicua 🇺🇸 730 37 35ms 27 Dec 2023 67th Lv0Sys 🇵🇱 730 37 36ms 28 Nov 2025 75th graft 711 38 36ms 11 Mar 2018 75th nexaitch 711 38 38ms 7 Jul 2020 75th galloj 🇨🇿 711 38 36ms 14 Sep 2022 75th RuyiLi 711 38 36ms 7 Apr 2023 75th tatzyr 🇯🇵 711 38 38ms 8 Jan 2025 75th ejini6969 711 38 37ms 13 Jun 2025 1–80 of 185 Next Last