The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 days. Why not try and solve them ahead of time?
Catalan 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 229th alemelis 733 60 10ms 13 Oct 2024 229th csharpython 733 60 10ms 5 Aug 2025 229th BREMAUCY 🇫🇷 733 60 10ms 11 Aug 2025 229th denkyuu1 733 60 11ms 16 Feb 2026 245th knutae 🇳🇴 721 61 10ms 3 Feb 2022 245th cros107 🇦🇺 721 61 10ms 2 Nov 2022 245th Baxi-codes 721 61 10ms 24 Dec 2022 245th thatbirdguythatuknownot 721 61 9ms 14 Jan 2023 245th mathb0y512 721 61 9ms 20 Apr 2023 245th Mikey-Beep 🇬🇧 721 61 10ms 31 Aug 2023 245th drochom 721 61 10ms 17 Jun 2024 245th tphLatte 721 61 9ms 3 Jul 2024 245th NanduBC 721 61 10ms 6 Sep 2024 245th Pyroan 721 61 9ms 13 May 2025 245th Tristanchaang 721 61 10ms 15 Nov 2025 256th CedricGebistorf 710 62 10ms 6 Feb 2022 256th Indivicivet 710 62 10ms 9 May 2022 256th MaxElf999 710 62 10ms 24 May 2022 256th rowboat1 710 62 10ms 18 Jun 2022 256th jfallon1997 710 62 10ms 8 Aug 2022 256th NerdyMcNerd42 710 62 10ms 13 Aug 2022 256th Ripick 710 62 9ms 23 Aug 2022 256th EyalLitvin 710 62 10ms 18 Nov 2022 256th Omega65536 🇩🇪 710 62 11ms 24 Nov 2022 256th badboj40 710 62 28ms 27 Dec 2022 256th b10011 🇫🇮 710 62 10ms 8 Jan 2023 256th MichalMarsalek 🇨🇿 710 62 10ms 14 Jan 2023 256th eiburns 710 62 10ms 22 Jan 2023 256th celiendonze 🇨🇭 710 62 10ms 8 Apr 2023 256th Vaekor 710 62 10ms 9 Jul 2023 256th estomagordo 🇳🇱 710 62 10ms 31 Aug 2023 256th rollershutter 710 62 10ms 23 Oct 2023 256th azure-blondon 710 62 9ms 14 Dec 2023 256th chartung17 710 62 10ms 17 Dec 2023 256th mikehanus 710 62 9ms 29 Jan 2024 256th ThijsLuttikhuis 710 62 10ms 1 Mar 2024 256th KingSkyrock 🇺🇸 710 62 10ms 26 Mar 2024 256th kejcao 🇨🇦 710 62 10ms 16 May 2024 256th CutSandstone 710 62 10ms 4 Jul 2024 256th jiaminglimjm 🇲🇾 710 62 10ms 5 Jul 2024 256th Mathrew2012 710 62 9ms 30 Aug 2024 256th croc54 710 62 10ms 21 Dec 2024 256th Rampoina 710 62 9ms 24 May 2025 256th ValentinCassayre 710 62 10ms 22 Sep 2025 256th Voltrifrodec 🇸🇰 710 62 10ms 18 Nov 2025 286th Jasper-Ty 🇵🇭 698 63 10ms 19 Jun 2022 286th jamespeilunli 698 63 10ms 4 Jul 2022 286th Starwort 🇬🇧 698 63 10ms 11 Nov 2022 286th thomasklunker 698 63 10ms 3 Feb 2023 286th VV1Git 698 63 10ms 19 Apr 2023 286th lucasalavapena 698 63 10ms 11 Dec 2023 286th Techdude01 698 63 9ms 22 Dec 2023 286th LostSyntax21 🇬🇧 698 63 9ms 20 Sep 2024 286th allen-brandon 698 63 10ms 30 Jul 2025 295th argusdusty 🇺🇸 688 64 12ms 21 Aug 2022 295th BraedenMooreDev 688 64 10ms 29 Oct 2023 297th P-Quentin 🇫🇷 677 65 10ms 11 Aug 2022 297th wh3n3v3r 🇨🇿 677 65 9ms 12 Nov 2024 297th robin-scragg 677 65 11ms 29 Jul 2025 300th firegene 🇮🇪 667 66 14ms 25 days ago 301st Drew-j-Smith 657 67 64ms 2 May 2022 301st Shiran-Yuan 657 67 9ms 5 Apr 2023 301st Pale-Vessel 657 67 10ms 1 Apr 2024 301st JKfromHMS 657 67 9ms 20 May 2024 301st nickphe 657 67 10ms 19 Aug 2024 301st Unknownuserfrommars 657 67 10ms 20 Nov 2024 301st jusaka 657 67 10ms 6 days ago 308th JGDoerrer 638 69 10ms 29 Jan 2022 309th 4hg 🇺🇸 629 70 17ms 27 Jan 2023 309th davbass 🇮🇹 629 70 10ms 29 Dec 2023 311th vodker1 620 71 10ms 9 Mar 2022 311th mdnestor 620 71 15ms 14 Dec 2022 311th juliusgeo 620 71 9ms 4 Feb 2023 311th aalec 620 71 64ms 4 May 2024 311th simplylu 620 71 10ms 5 Jan 2025 316th jmerle 🇳🇱 611 72 13ms 31 Oct 2022 316th scpchicken 🇵🇼 611 72 11ms 18 Mar 2023 316th 0xBenCantCode 611 72 10ms 13 May 2023 319th HumanEquivalentUnit 603 73 10ms 12 Feb 2022 319th AdamHe17 603 73 18ms 15 Aug 2022 First Prev 241–320 of 430 Next Last