The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 2 days. Why not try and solve them ahead of time?
Happy Numbers in all languages 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 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 Bytes Time Submitted 477th saito-ta 🇯🇵 915 91 1ms 3 Oct 2022 477th retrohun 915 91 1ms 30 Apr 2023 477th btnlq 915 91 1ms 17 May 2023 477th kritixilithos 915 91 1ms 22 May 2024 485th edsrzf 🇳🇿 912 61 901ms 15 Sep 2025 485th sean-niemann 🇺🇸 912 61 1,017ms 16 Sep 2025 485th DialFrost 🇸🇬 912 61 826ms 12 Nov 2025 485th Yewzir 🇧🇪 912 61 919ms 16 Nov 2025 485th Steffan153 🇫🇮 912 61 732ms 14 Feb 2026 485th dokutan 912 61 709ms 16 days ago 491st MeWhenI 🇻🇦 912 62 124ms 11 Nov 2021 492nd sisyphus-ppcg 🇦🇺 911 77 3ms 3 Feb 2023 493rd Shanethegamer 🇺🇸 910 63 71ms 18 May 2022 493rd Yewzir 🇧🇪 910 63 72ms 9 Nov 2023 493rd Betuaredead 910 63 70ms 13 Nov 2023 493rd albanian-laundromat 910 63 71ms 8 Nov 2025 493rd snoozingnewt 🇨🇦 910 63 71ms 6 Dec 2025 498th Steffan153 🇫🇮 910 72 1ms 26 Feb 2026 498th JayXon 🇺🇸 910 72 2ms 3 days ago 500th Lydxn 🇨🇦 910 74 37ms 14 Jul 2021 500th JayXon 🇺🇸 910 74 38ms 20 Aug 2021 500th stefangimmillaro 910 74 39ms 22 Apr 2023 503rd sisyphus-ppcg 🇦🇺 910 91 1ms 20 Jul 2022 503rd UnderKoen 🇳🇱 910 91 2ms 6 Mar 2023 503rd m-tkach 🇺🇦 910 91 1ms 9 Mar 2023 503rd Lydxn 🇨🇦 910 91 2ms 19 Jul 2023 507th pihart 909 66 11ms 22 Jun 2020 507th Argeento 🇵🇱 909 66 11ms 13 Nov 2020 507th ovs-code 🇩🇪 909 66 12ms 29 Jul 2024 507th Lv0Sys 🇵🇱 909 66 11ms 29 Nov 2025 511th dvargas46 🇺🇸 908 55 53ms 15 Nov 2022 512th Waffle3z 908 74 1ms 9 Jul 2021 513th Lydxn 🇨🇦 908 85 458ms 27 Feb 2022 513th JayXon 🇺🇸 908 85 462ms 28 Feb 2022 513th GrayJoKing 🇦🇺 908 85 462ms 13 Mar 2022 516th anter69 🇭🇺 907 55 1,259ms 10 Mar 2025 517th MeWhenI 🇻🇦 907 67 4ms 16 Dec 2024 517th Yewzir 🇧🇪 907 67 5ms 20 Dec 2024 517th GrayJoKing 🇦🇺 907 67 5ms 31 Jan 2025 520th prplz 🇦🇺 907 75 145ms 12 Oct 2021 520th YAJUE114514 907 75 139ms 30 Jul 2025 522nd fuzzylojik-golf 🇺🇸 907 81 373ms 7 Sep 2025 523rd frankgraziano 907 144 10ms 11 Aug 2025 523rd primo-ppcg 🇹🇭 907 144 10ms 13 Aug 2025 523rd DialFrost 🇸🇬 907 144 9ms 13 Aug 2025 526th sisyphus-ppcg 🇦🇺 906 64 73ms 12 Dec 2022 526th Lydxn 🇨🇦 906 64 73ms 13 Dec 2022 526th ovs-code 🇩🇪 906 64 70ms 21 Apr 2024 526th DialFrost 🇸🇬 906 64 74ms 20 Feb 2025 526th sean-niemann 🇺🇸 906 64 72ms 20 Feb 2025 526th snoozingnewt 🇨🇦 906 64 71ms 29 Nov 2025 532nd Steffan153 🇫🇮 906 91 27ms 28 Jan 2023 532nd GrayJoKing 🇦🇺 906 91 28ms 28 Jan 2023 532nd Lydxn 🇨🇦 906 91 27ms 28 Jan 2023 532nd m-tkach 🇺🇦 906 91 28ms 18 Jan 2024 532nd sean-niemann 🇺🇸 906 91 27ms 19 May 2025 537th Yax42 🇫🇷 906 92 494ms 12 Nov 2025 538th MeWhenI 🇻🇦 905 65 6ms 12 Dec 2023 539th canissimia 🇦🇶 905 194 4ms 21 Sep 2021 540th lynn 904 79 1ms 2 Oct 2021 540th MeWhenI 🇻🇦 904 79 2ms 21 Jun 2022 540th m-tkach 🇺🇦 904 79 1ms 9 Mar 2023 540th ovs-code 🇩🇪 904 79 2ms 24 Mar 2024 540th xsot 🇸🇬 904 79 1ms 23 May 2024 540th DialFrost 🇸🇬 904 79 10ms 17 Dec 2024 546th janbehrens 🇩🇪 903 70 4ms 26 Nov 2023 547th emplv 🇱🇻 903 77 106ms 14 Mar 2023 548th Lydxn 🇨🇦 903 91 26ms 16 Apr 2022 548th JayXon 🇺🇸 903 91 24ms 17 Apr 2022 548th m-tkach 🇺🇦 903 91 24ms 9 Mar 2023 551st rucin93 🇵🇱 902 64 159ms 6 Sep 2024 552nd edsrzf 🇳🇿 901 92 2ms 24 Feb 2026 553rd tailorspy 901 96 59ms 22 Sep 2024 554th juliansiebert 🇩🇪 900 55 296ms 31 Jul 2022 555th MeWhenI 🇻🇦 899 75 4ms 22 Mar 2024 556th Shanethegamer 🇺🇸 899 78 105ms 7 Nov 2025 556th emgordon154 899 78 113ms 27 Nov 2025 556th GolfingSuccess 🇬🇷 899 78 101ms 28 Nov 2025 556th edsrzf 🇳🇿 899 78 132ms 28 Nov 2025 556th DialFrost 🇸🇬 899 78 101ms 28 Nov 2025 First Prev 481–560 of 3,221 Next Last