The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 4 days. Why not try and solve them ahead of time?
Happy Numbers (Long) 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 Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions 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 Multitap Input 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 Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> ALGOL 68 ArkScript 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 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> ALGOL 68 ArkScript 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 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily 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 Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions 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 Multitap Input 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 Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Chars Time Submitted 801st frankgraziano 733 100 9ms 24 Feb 2026 802nd j-Ewan 732 41 33ms 22 Feb 2022 802nd sisyphus-ppcg 🇦🇺 732 41 217ms 31 Jan 2023 802nd SirFireball3521 732 41 262ms 15 Mar 2023 805th jared-hughes 732 81 283ms 19 Sep 2021 805th jacklynnepenick 732 81 200ms 5 Nov 2021 805th guilhem-roy 🇫🇷 732 81 301ms 26 Feb 2022 805th suwat513 732 81 301ms 15 Sep 2022 805th LogicalJoe 732 81 219ms 7 Oct 2022 805th Eilonlif 🇮🇱 732 81 307ms 3 Nov 2022 805th janbehrens 🇩🇪 732 81 219ms 17 Jun 2023 805th bknower 732 81 24ms 26 Jun 2025 805th edsrzf 🇳🇿 732 81 218ms 22 Jul 2025 814th janbehrens 🇩🇪 731 64 471ms 9 Nov 2021 814th dokutan 731 64 338ms 14 days ago 816th AlephSquirrel 731 81 11ms 8 Aug 2022 816th Program-Pi 731 81 11ms 22 days ago 818th jared-hughes 731 94 2ms 14 Mar 2022 818th KenanHanke 731 94 2ms 22 Feb 2023 820th snoozingnewt 🇨🇦 731 136 154ms 29 Sep 2025 821st primo-ppcg 🇹🇭 730 104 391ms 21 Nov 2021 821st Irratix 🇳🇱 730 104 385ms 13 Dec 2021 821st ericlangedijk 🇸🇮 730 104 444ms 17 Mar 2022 821st CaedenHarper 🇨🇦 730 104 381ms 5 Nov 2025 821st prestosilver 🇺🇸 730 104 133ms 10 days ago 826th Shanethegamer 🇺🇸 729 104 15ms 17 Dec 2023 827th dokutan 729 109 108ms 18 Nov 2025 828th MeWhenI 🇻🇦 728 68 1,795ms 28 Jan 2023 828th Feniske 🇫🇷 728 68 1,687ms 7 Nov 2023 830th MeWhenI 🇻🇦 728 73 163ms 3 Aug 2024 831st neel11235813 728 77 451ms 15 Jan 2024 831st CaedenHarper 🇨🇦 728 77 649ms 14 Jul 2025 833rd snoozingnewt 🇨🇦 728 84 91ms 22 Oct 2025 834th DialFrost 🇸🇬 728 91 23ms 31 Oct 2023 835th GrayJoKing 🇦🇺 728 113 459ms 28 Feb 2022 836th snoozingnewt 🇨🇦 727 105 38ms 1 Sep 2024 837th jerrandolph 727 162 290ms 3 Nov 2023 838th Yewzir 🇧🇪 726 90 43ms 14 Jan 2024 839th Schmitt-Very-Cool 726 128 348ms 30 Sep 2025 840th scpchicken 🇵🇼 726 137 156ms 19 May 2022 841st AlephSquirrel 724 95 2ms 8 Jun 2023 842nd albanian-laundromat 724 190 1,414ms 18 Oct 2025 843rd Shanethegamer 🇺🇸 723 57 99ms 27 Sep 2021 844th stefangimmillaro 723 82 312ms 27 Sep 2021 844th NewDefectus 🇮🇱 723 82 20ms 16 Dec 2021 844th CedricGebistorf 723 82 228ms 25 Feb 2022 844th aksyristos 723 82 198ms 12 Feb 2023 844th quimey 723 82 219ms 22 Mar 2023 844th StefanHabel 🇨🇦 723 82 301ms 26 Mar 2023 844th Fracture17 723 82 268ms 8 Apr 2023 844th Re-Adventures 🇮🇳 723 82 216ms 20 Jul 2023 844th Natanaelel 🇸🇪 723 82 217ms 29 Oct 2023 844th codingisgreatbutiamnot 723 82 300ms 25 Jul 2024 844th klixel 🇨🇦 723 82 300ms 17 Jan 2025 844th blaztoma 🇱🇹 723 82 264ms 15 Nov 2025 844th CommandLeo 🇮🇹 723 82 300ms 3 Dec 2025 844th luuumine 🇫🇷 723 82 305ms 4 Dec 2025 844th FortuiteMan 🇫🇷 723 82 296ms 5 Dec 2025 844th FoxInTheClouds 723 82 218ms 13 Feb 2026 860th arctouch-cristiannevianna 723 105 427ms 26 May 2023 860th annaproxy 723 105 452ms 11 Apr 2025 860th snoozingnewt 🇨🇦 723 105 123ms 3 Oct 2025 863rd randolchance 722 82 13ms 11 Jan 2023 863rd Protothor 722 82 15ms 26 Feb 2026 865th annaproxy 721 105 26ms 8 Jan 2023 866th Shanethegamer 🇺🇸 721 121 36ms 15 Dec 2022 867th MeWhenI 🇻🇦 720 118 41ms 13 Feb 2025 868th GolfingSuccess 🇬🇷 719 112 4ms 11 Sep 2022 869th Shanethegamer 🇺🇸 718 74 162ms 19 Aug 2024 870th RockOfStone 718 106 2ms 4 Nov 2021 871st targrik 718 164 281ms 30 Jun 2025 872nd dcgjb 717 69 1,080ms 6 May 2024 873rd prplz 🇦🇺 715 42 239ms 27 Sep 2021 874th neihousaigaai 715 83 20ms 3 Jan 2022 874th cesarm4 715 83 181ms 16 Apr 2022 874th nstearns96 🇬🇧 715 83 245ms 27 Jan 2023 874th randolchance 715 83 20ms 16 Feb 2023 874th galloj 🇨🇿 715 83 3,418ms 5 Mar 2023 874th yzhs 🇩🇪 715 83 236ms 23 Jun 2023 874th m42km 715 83 312ms 12 Oct 2023 First Prev 801–880 of 2,088 Next Last