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 800th GrayJoKing 🇦🇺 866 81 2ms 12 Feb 2023 802nd jared-hughes 865 100 52ms 20 Jul 2022 803rd emgordon154 863 30 43ms 10 Sep 2025 804th annaproxy 863 46 2ms 18 Feb 2022 805th CornerMercury 🇬🇧 862 29 3ms 21 Jan 2026 805th emgordon154 862 29 3ms 22 Feb 2026 807th MeWhenI 🇻🇦 861 78 1ms 27 Dec 2022 808th treeowl 861 79 135ms 27 Feb 2019 808th user189032 861 79 136ms 29 May 2019 808th cbrt-x 861 79 137ms 15 Sep 2023 811th emgordon154 860 58 1,297ms 22 Dec 2021 812th DaCuteRaccoon 860 65 2ms 30 Nov 2022 812th snoozingnewt 🇨🇦 860 65 4ms 1 Sep 2024 812th LostSyntax21 🇬🇧 860 65 2ms 8 Jan 2025 815th m-tkach 🇺🇦 860 77 2ms 5 Dec 2023 816th gilufin 858 55 167ms 30 May 2021 816th Natanaelel 🇸🇪 858 55 38ms 10 May 2023 816th denkyuu1 858 55 40ms 15 Feb 2026 819th emgordon154 858 90 484ms 8 Feb 2026 820th stefangimmillaro 857 66 125ms 15 Jul 2023 821st GrayJoKing 🇦🇺 857 70 11ms 20 Sep 2021 821st 0x24a537r9 857 70 13ms 10 Sep 2022 823rd JDiLenarda 🇫🇷 856 71 1,207ms 9 Oct 2020 823rd MeWhenI 🇻🇦 856 71 2,898ms 24 Oct 2024 823rd sean-niemann 🇺🇸 856 71 2,571ms 30 Oct 2024 823rd jkelly467 856 71 2,525ms 3 Nov 2025 827th MeWhenI 🇻🇦 856 75 35ms 20 Jun 2022 827th sean-niemann 🇺🇸 856 75 39ms 19 Nov 2024 829th MeWhenI 🇻🇦 856 101 53ms 8 May 2022 829th janbehrens 🇩🇪 856 101 60ms 26 Nov 2023 831st ovs-code 🇩🇪 855 44 156ms 31 Dec 2023 832nd clockworknazo 855 82 5ms 13 Oct 2022 832nd ovs-code 🇩🇪 855 82 5ms 7 Feb 2023 832nd Lydxn 🇨🇦 855 82 4ms 28 Feb 2023 835th ScottHamper 855 86 373ms 21 Nov 2021 835th amazingalek 🇳🇴 855 86 387ms 27 Dec 2025 837th ovs-code 🇩🇪 852 62 405ms 2 Mar 2024 837th BREMAUCY 🇫🇷 852 62 374ms 6 Dec 2025 839th btnlq 851 68 3ms 16 Jul 2023 840th GolfingSuccess 🇬🇷 851 77 1ms 19 Mar 2025 840th sean-niemann 🇺🇸 851 77 1ms 19 Nov 2025 842nd Yewzir 🇧🇪 851 98 354ms 2 Oct 2025 843rd DialFrost 🇸🇬 850 79 1ms 26 Dec 2024 844th RussellEmerine 850 80 138ms 30 Nov 2019 844th iczelia 🇩🇪 850 80 159ms 20 Oct 2025 846th NewDefectus 🇮🇱 850 84 2ms 16 Dec 2021 847th ovs-code 🇩🇪 849 68 149ms 3 Aug 2024 848th DialFrost 🇸🇬 849 78 2ms 26 Dec 2024 849th prplz 🇦🇺 847 96 124ms 30 Apr 2022 849th elgan65536 🇺🇸 847 96 167ms 11 Nov 2023 851st kg583 🇺🇸 846 95 40ms 26 Jul 2025 852nd lynn 845 59 1,255ms 25 May 2022 852nd DialFrost 🇸🇬 845 59 1,322ms 26 Dec 2024 852nd janlelis 845 59 1,323ms 14 Aug 2025 852nd dokutan 845 59 1,213ms 16 days ago 856th jared-hughes 845 71 9ms 29 Oct 2021 856th stefangimmillaro 845 71 10ms 27 Aug 2022 856th Maznek 845 71 13ms 19 Jun 2023 856th snoozingnewt 🇨🇦 845 71 12ms 29 Nov 2025 860th primo-ppcg 🇹🇭 844 67 123ms 27 Mar 2021 860th snoozingnewt 🇨🇦 844 67 123ms 29 Nov 2025 862nd Frowny 844 72 9ms 3 Jul 2020 862nd lifthrasiir 🇰🇷 844 72 10ms 13 Nov 2024 864th snoozingnewt 🇨🇦 843 66 884ms 29 Nov 2025 865th villfa 842 75 14ms 30 Nov 2018 865th LostSyntax21 🇬🇧 842 75 14ms 8 Jan 2025 867th Jacob385 842 99 516ms 27 Oct 2025 868th jslip 841 35 33ms 5 Sep 2018 868th rak1507 🇬🇧 841 35 34ms 20 Sep 2021 870th Steffan153 🇫🇮 841 99 1ms 28 Jan 2023 870th pardouin 🇫🇷 841 99 1ms 21 Sep 2024 870th sean-niemann 🇺🇸 841 99 1ms 9 May 2025 873rd Laar 840 81 137ms 1 Apr 2019 873rd alomiF 840 81 136ms 5 Oct 2023 873rd brimstonetrader 840 81 115ms 26 Jan 2024 876th annaproxy 840 85 1ms 18 May 2023 877th AdrienHache 🇫🇷 840 103 58ms 7 Jan 2024 877th emgordon154 840 103 60ms 7 Feb 2026 879th HumanEquivalentUnit 839 59 349ms 10 Oct 2020 879th madex 🇩🇪 839 59 474ms 13 days ago First Prev 801–880 of 3,221 Next Last