The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 3 days. Why not try and solve them ahead of time?
Happy Numbers in Python 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 561st rschwa6308 🇺🇸 381 126 18ms 6 Aug 2020 561st jackedwards04 381 126 9ms 22 Nov 2020 561st b4dpxl 381 126 16ms 10 Nov 2021 561st jettdc 381 126 10ms 31 Dec 2022 561st jstechman 381 126 10ms 9 Mar 2024 566th usnheckler 378 127 64ms 7 Jun 2019 566th derekthatcher 378 127 16ms 25 Sep 2020 566th bastienvoirin 🇫🇷 378 127 18ms 28 Nov 2020 566th Evan-Robotics 378 127 16ms 26 Jan 2022 566th gareth-kmet 378 127 16ms 2 Mar 2023 571st petar-donchev 375 128 11ms 8 Sep 2019 571st shibacho 🇯🇵 375 128 18ms 25 Nov 2022 571st EthanJantz 375 128 17ms 27 Aug 2025 574th ChristianFieldhouse 372 129 10ms 22 Mar 2021 575th richard-oelze 🇩🇪 369 130 17ms 28 Feb 2021 575th yokasuretsu 369 130 11ms 28 Nov 2021 575th andrewgopher 369 130 11ms 27 Jun 2022 575th LukasFolwarczny 🇨🇿 369 130 18ms 16 Sep 2022 575th ellis-rix 369 130 11ms 27 Jan 2023 575th Coding4Hours 369 130 16ms 4 Oct 2024 575th IsaacAlexBarden 369 130 12ms 13 Feb 2025 582nd ozewski 366 131 72ms 2 May 2019 582nd guliyevemil1 🇦🇿 366 131 10ms 18 Apr 2020 582nd Gordo5556 366 131 10ms 29 Apr 2022 585th theonlytruemathnerd 364 132 17ms 11 Jan 2020 585th JuanGomez12 364 132 10ms 2 Feb 2023 585th aszku 364 132 10ms 20 Apr 2023 585th strogor 364 132 11ms 9 Jun 2025 589th Manby 361 133 11ms 30 Jun 2021 589th byteDJINN 361 133 17ms 16 Jan 2024 589th FusionAtom360 361 133 18ms 4 Jan 2026 592nd skps2010 358 134 9ms 4 Jan 2019 592nd patbassing 358 134 11ms 26 May 2019 592nd Nibamot 358 134 10ms 19 Feb 2020 592nd aagray33 358 134 10ms 28 Feb 2020 592nd Techdude01 358 134 16ms 17 Dec 2022 592nd julian-hoelz 358 134 10ms 15 Sep 2024 598th bkshrader 356 135 17ms 27 Dec 2018 598th reubengann 356 135 10ms 14 Feb 2020 598th DGipe 356 135 11ms 22 Oct 2025 601st smartiel 353 136 11ms 15 Sep 2022 601st ComputerKWasTaken 🇺🇸 353 136 17ms 8 Jun 2024 603rd DrPrettyman 350 137 11ms 1 Jun 2023 604th adamhass 348 138 11ms 19 Jul 2018 604th mrmena 🇦🇺 348 138 17ms 16 Apr 2024 606th jmhowl 345 139 17ms 19 Jan 2020 606th mokymok 🇺🇸 345 139 17ms 29 Dec 2021 606th lightediand 🇬🇧 345 139 11ms 18 Jan 2023 606th CyberTapir 345 139 11ms 1 Sep 2024 606th Wonamm 345 139 12ms 14 Feb 2025 606th TJK-S 345 139 10ms 22 Oct 2025 612th mcdowell95 343 140 10ms 26 Mar 2020 612th osmith93 343 140 11ms 31 Jul 2021 612th 104210 343 140 10ms 11 May 2022 615th Pierrot-Baptiste 340 141 11ms 9 Aug 2020 615th dranjohn 340 141 9ms 10 Sep 2023 615th SURAJMITTAL 340 141 11ms 20 Dec 2024 618th ChristophJud 338 142 10ms 11 Aug 2020 618th ESOrSomething 338 142 11ms 29 Sep 2025 620th RoscoeSmith 336 143 11ms 14 Sep 2022 621st SimonPeatman 333 144 17ms 2 Feb 2019 621st pde-bakk 🇳🇱 333 144 11ms 23 Oct 2023 623rd CRHillman 331 145 17ms 17 Aug 2018 623rd ethandhunt 331 145 10ms 29 Jul 2021 625th KiwiKoder0123 329 146 11ms 24 Jun 2019 625th KatieLG-Transpiler 🇬🇧 329 146 9ms 23 Jun 2022 625th twocatsinatrenchcoat 329 146 9ms 18 Nov 2022 625th fraserli 🇦🇺 329 146 16ms 17 Feb 2023 625th zt14427 329 146 10ms 4 Mar 2023 625th Schmitt-Very-Cool 329 146 11ms 3 Apr 2024 631st potato-jackson 327 147 17ms 10 Sep 2021 631st Florian-Mt 327 147 18ms 26 Sep 2023 633rd Mojken 324 148 19ms 2 Sep 2018 633rd NoneTheFewer 324 148 16ms 25 Dec 2025 635th snickercop 322 149 11ms 6 Aug 2019 636th ionutm82 320 150 10ms 22 Feb 2019 637th dahrens 318 151 11ms 7 Jul 2019 638th fepe55 316 152 9ms 21 Sep 2018 639th ari-gutierrez 310 155 33ms 22 Oct 2018 640th Spi3lot 306 157 9ms 18 Sep 2021 First Prev 561–640 of 712 Next Last
