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 641st snoozingnewt 🇨🇦 715 82 2ms 13 Oct 2025 642nd emplv 🇱🇻 713 118 26ms 29 Jun 2022 643rd mauro-1 🇮🇹 712 72 17ms 18 Aug 2021 643rd PiterAnnema 712 72 39ms 23 Mar 2022 643rd Andrey135296 712 72 11ms 4 Apr 2022 643rd TaserTheFox 🇺🇸 712 72 12ms 27 Jan 2023 643rd Fracture17 712 72 38ms 13 Apr 2023 643rd WillConker 712 72 48ms 10 Mar 2024 643rd jipsong 🇩🇪 712 72 19ms 10 Jun 2024 643rd CutSandstone 712 72 36ms 5 Jul 2024 651st sean-niemann 🇺🇸 710 110 130ms 9 Jun 2025 652nd rak1507 🇬🇧 709 76 137ms 29 Jun 2021 652nd GrayJoKing 🇦🇺 709 76 130ms 14 Mar 2022 654th emgordon154 708 52 41ms 27 Nov 2024 654th olleicua 🇺🇸 708 52 46ms 25 Feb 2025 654th codereport 🇨🇦 708 52 33ms 21 Apr 2025 654th snoozingnewt 🇨🇦 708 52 38ms 13 Oct 2025 658th dokutan 708 68 474ms 12 Feb 2025 659th Irratix 🇳🇱 708 111 63ms 3 Jan 2022 659th Yewzir 🇧🇪 708 111 59ms 11 Feb 2024 661st KatieLG 🇬🇧 707 56 1,480ms 13 Oct 2021 662nd emgordon154 707 203 1,463ms 6 Nov 2025 663rd jared-hughes 705 51 6ms 17 Jul 2022 664th razetime 704 29 3ms 13 Jan 2022 665th Shanethegamer 🇺🇸 704 34 34ms 6 May 2021 665th MeWhenI 🇻🇦 704 34 34ms 9 Nov 2021 665th sisyphus-ppcg 🇦🇺 704 34 34ms 2 Mar 2022 668th snoozingnewt 🇨🇦 703 69 2ms 13 Oct 2025 669th MeWhenI 🇻🇦 703 194 1,704ms 7 Nov 2025 670th albanian-laundromat 702 55 2ms 11 days ago 671st Irratix 🇳🇱 702 73 43ms 7 May 2022 671st fredrik-bakke 🇳🇴 702 73 38ms 2 Oct 2022 671st fourth-bit 702 73 50ms 5 Dec 2022 671st CatsAreFluffy 702 73 22ms 17 Dec 2022 671st jmerle 🇳🇱 702 73 70ms 16 Feb 2023 671st AlexanderFair 702 73 47ms 2 Jul 2023 671st NickTheEASDude 🇺🇸 702 73 46ms 6 Aug 2024 671st AtengChen 702 73 11ms 27 Aug 2024 671st andrewjc2000 702 73 50ms 18 Jul 2025 671st madeforlosers 702 73 11ms 13 Nov 2025 681st Herbert00709 🇵🇱 702 112 56ms 1 Nov 2024 682nd GolfingSuccess 🇬🇷 701 81 18ms 11 Sep 2022 683rd albanian-laundromat 701 120 26ms 11 days ago 684th commandz0 🇺🇸 698 69 493ms 15 Jan 2024 684th TheZwierzLF 🇵🇱 698 69 469ms 22 Nov 2025 686th luuumine 🇫🇷 698 112 123ms 16 Nov 2025 687th MeWhenI 🇻🇦 697 114 27ms 7 Jun 2023 688th Shanethegamer 🇺🇸 696 73 27ms 28 Apr 2023 689th oceko 696 113 63ms 19 Feb 2024 690th frankgraziano 695 245 15ms 30 Sep 2025 691st adoxography 694 53 41ms 20 Aug 2021 691st schachmattmatt 694 53 38ms 25 Sep 2021 691st tatzyr 🇯🇵 694 53 44ms 18 Jan 2025 694th ovs-code 🇩🇪 694 86 5ms 21 Jul 2024 695th MeWhenI 🇻🇦 694 90 41ms 17 Feb 2023 696th adoxography 693 74 49ms 20 Aug 2021 696th m42km 693 74 11ms 25 Nov 2023 696th Stockoh 🇫🇷 693 74 44ms 23 Jun 2024 696th TheZwierzLF 🇵🇱 693 74 11ms 24 May 2025 700th DialFrost 🇸🇬 692 52 10ms 29 Dec 2025 701st ian-h-chamberlain 🇺🇸 692 113 128ms 6 Jul 2022 702nd Shanethegamer 🇺🇸 691 73 50ms 8 Apr 2024 703rd arjanadriaanse 🇳🇱 691 78 141ms 10 Feb 2022 703rd Shanethegamer 🇺🇸 691 78 116ms 15 Oct 2022 703rd tobeannouncd 691 78 1,395ms 8 Jan 2024 706th MeWhenI 🇻🇦 690 56 2ms 4 Nov 2022 707th emgordon154 689 85 2ms 24 Dec 2021 708th Shanethegamer 🇺🇸 689 111 457ms 25 Sep 2025 708th snoozingnewt 🇨🇦 689 111 431ms 13 Oct 2025 710th o0lit3 🇺🇸 688 45 12ms 4 May 2021 711th JunkIce 688 70 429ms 3 Dec 2024 712th albanian-laundromat 687 248 13ms 18 Sep 2025 713th potato-jackson 684 75 12ms 10 Sep 2021 713th osmith93 684 75 21ms 14 Jun 2022 713th aksyristos 684 75 46ms 18 Jan 2023 713th celiendonze 🇨🇭 684 75 12ms 11 Apr 2023 713th programjames 684 75 41ms 3 Feb 2024 713th bob-th 684 75 18ms 26 Jul 2024 713th fkantelberg 684 75 41ms 22 Jul 2025 720th msbranicky 684 83 2ms 4 Aug 2023 First Prev 641–720 of 1,855 Next Last