The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 8 days. Why not try and solve them ahead of time?
Van Eck Sequence 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 400th stefangimmillaro 832 92 443ms 6 Oct 2025 402nd lynn 829 83 1,436ms 13 Sep 2021 403rd Shanethegamer 🇺🇸 828 64 145ms 24 May 2021 404th GolfingSuccess 🇬🇷 828 95 59ms 2 Jan 2022 405th edsrzf 🇳🇿 828 114 298ms 8 Nov 2024 406th zacjl 827 61 49ms 15 Dec 2024 407th Kloppermand 🇩🇰 827 62 11ms 23 Sep 2021 407th guilhem-roy 🇫🇷 827 62 11ms 24 Feb 2022 407th CedricGebistorf 827 62 16ms 26 Feb 2022 407th inventshah 827 62 45ms 15 Nov 2022 407th QuincyNash 🇺🇸 827 62 51ms 5 Dec 2022 407th StefanHabel 🇨🇦 827 62 11ms 20 Dec 2022 407th thehylian 827 62 12ms 26 Dec 2022 407th davecame 827 62 12ms 17 Nov 2023 407th Lewenhaupt 827 62 11ms 26 Apr 2024 407th HumanoidCPU 827 62 12ms 25 May 2024 407th dirckvdende 827 62 11ms 21 Jul 2025 418th lynn 825 29 35ms 1 May 2021 419th jared-hughes 825 71 2ms 17 Mar 2022 419th LorenzoDeGaspari 825 71 2ms 26 Jul 2022 419th 09cf 825 71 2ms 8 Oct 2023 419th AZTECCO 825 71 2ms 17 Sep 2025 423rd stefangimmillaro 825 88 379ms 5 May 2023 423rd Yax42 🇫🇷 825 88 440ms 16 Aug 2025 425th MeWhenI 🇻🇦 823 93 575ms 7 Nov 2025 426th stefangimmillaro 823 95 127ms 28 May 2024 427th Lydxn 🇨🇦 822 54 100ms 28 Jun 2023 428th GolfingSuccess 🇬🇷 822 89 42ms 3 days ago 429th albanian-laundromat 821 76 42ms 6 Sep 2025 429th DialFrost 🇸🇬 821 76 43ms 30 Dec 2025 431st neihousaigaai 820 50 12ms 3 May 2021 431st uttumuttu 🇫🇮 820 50 11ms 8 Jan 2022 431st jared-hughes 820 50 12ms 6 Apr 2022 431st janbehrens 🇩🇪 820 50 11ms 31 May 2022 431st inventshah 820 50 12ms 15 Nov 2022 431st Maznek 820 50 9ms 28 Jun 2023 431st voytxt 🇨🇿 820 50 10ms 11 Jul 2024 431st Lv0Sys 🇵🇱 820 50 13ms 5 Dec 2025 439th primo-ppcg 🇹🇭 820 64 131ms 6 Aug 2024 440th ovs-code 🇩🇪 820 88 456ms 14 Mar 2022 441st typeswitch-dev 🇵🇹 818 81 5ms 4 Aug 2023 442nd CaedenHarper 🇨🇦 817 55 835ms 17 Feb 2026 443rd GrayJoKing 🇦🇺 817 66 114ms 6 Feb 2023 443rd sean-niemann 🇺🇸 817 66 144ms 19 Jul 2024 445th KatieLG 🇬🇧 816 59 418ms 28 Oct 2024 446th primo-ppcg 🇹🇭 816 103 25ms 10 May 2023 447th nwellnhof 🇩🇪 815 38 11ms 14 Oct 2021 447th Steffan153 🇫🇮 815 38 3ms 29 Aug 2024 447th saito-ta 🇯🇵 815 38 3ms 4 Aug 2025 450th primo-ppcg 🇹🇭 815 65 142ms 11 Jul 2022 451st MeWhenI 🇻🇦 815 89 402ms 8 Dec 2022 452nd firegene 🇮🇪 814 63 40ms 5 Jan 2023 452nd hiichbindermax 814 63 11ms 17 Feb 2023 452nd wh3n3v3r 🇨🇿 814 63 17ms 14 Nov 2024 452nd Emutis 🇱🇹 814 63 11ms 15 Feb 2025 452nd solisolu 814 63 32ms 26 Nov 2025 457th prplz 🇦🇺 814 72 2ms 1 May 2021 457th NewDefectus 🇮🇱 814 72 2ms 3 May 2021 459th SirBogman 🇺🇸 812 40 578ms 9 Apr 2022 460th Steffan153 🇫🇮 811 89 438ms 23 Jul 2024 460th sean-niemann 🇺🇸 811 89 439ms 2 Jan 2025 462nd dcgjb 810 48 483ms 22 Feb 2024 462nd Steffan153 🇫🇮 810 48 376ms 9 Aug 2024 464th GrayJoKing 🇦🇺 809 61 8ms 11 Oct 2023 465th inventshah 809 80 2,631ms 12 Nov 2024 466th emgordon154 808 49 1,330ms 27 Nov 2024 467th clockworknazo 807 74 4ms 22 Nov 2022 468th emgordon154 807 169 1,740ms 16 Sep 2025 469th primo-ppcg 🇹🇭 806 63 5ms 16 Aug 2023 470th prplz 🇦🇺 806 90 373ms 21 Nov 2021 470th sean-niemann 🇺🇸 806 90 426ms 2 Jan 2025 472nd tayloia 🇬🇧 804 51 12ms 18 May 2023 473rd edsrzf 🇳🇿 803 56 1,048ms 4 Sep 2025 473rd albanian-laundromat 803 56 1,094ms 4 Nov 2025 475th MeWhenI 🇻🇦 803 60 429ms 29 Apr 2025 476th lynn 802 99 29ms 18 Jul 2023 476th Steffan153 🇫🇮 802 99 28ms 25 Aug 2024 478th Just4FunCoder 801 64 20ms 23 Mar 2023 478th AlephSquirrel 801 64 37ms 18 Apr 2023 478th msbranicky 801 64 11ms 25 Jul 2023 First Prev 401–480 of 1,855 Next Last