The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 4 days. Why not try and solve them ahead of time?
Kaprekar Numbers 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 801st CLOStrophobic 🇮🇹 167 356 4,507ms 9 Feb 2025 802nd HumanoidCPU 167 455 2ms 1 Nov 2024 802nd KatieLG 🇬🇧 167 455 2ms 1 Nov 2024 802nd Shanethegamer 🇺🇸 167 455 2ms 1 Nov 2024 802nd MeWhenI 🇻🇦 167 455 2ms 2 Nov 2024 802nd CaedenHarper 🇨🇦 167 455 2ms 16 Aug 2025 807th Shanethegamer 🇺🇸 167 471 467ms 1 Nov 2024 808th KatieLG 🇬🇧 167 472 42ms 1 Nov 2024 808th MeWhenI 🇻🇦 167 472 494ms 2 Nov 2024 808th CaedenHarper 🇨🇦 167 472 448ms 24 Jan 2025 811th KatieLG-Transpiler 🇬🇧 166 459 2ms 9 Jan 2026 812th HumanoidCPU 166 473 464ms 1 Nov 2024 813th HumanoidCPU 165 441 3ms 1 Nov 2024 813th KatieLG 🇬🇧 165 441 3ms 1 Nov 2024 813th Shanethegamer 🇺🇸 165 441 3ms 1 Nov 2024 813th MeWhenI 🇻🇦 165 441 3ms 2 Nov 2024 813th CaedenHarper 🇨🇦 165 441 3ms 31 Jan 2025 813th KatieLG-Transpiler 🇬🇧 165 441 3ms 9 Jan 2026 819th MeWhenI 🇻🇦 165 445 2,374ms 2 Nov 2024 819th CaedenHarper 🇨🇦 165 445 2,340ms 1 Feb 2025 821st HumanoidCPU 165 458 404ms 1 Nov 2024 821st Shanethegamer 🇺🇸 165 458 402ms 1 Nov 2024 821st dokutan 165 458 401ms 1 Nov 2024 821st mwarvik 🇳🇴 165 458 417ms 5 Jan 2026 825th HumanoidCPU 162 452 2,438ms 1 Nov 2024 825th Shanethegamer 🇺🇸 162 452 2,490ms 1 Nov 2024 827th HumanoidCPU 160 657 30ms 4 Nov 2025 828th CaedenHarper 🇨🇦 159 659 26ms 16 Aug 2025 829th KatieLG-Transpiler 🇬🇧 159 660 26ms 9 Jan 2026 830th KatieLG-Transpiler 🇬🇧 157 972 4ms 9 Jan 2026 831st KatieLG-Transpiler 🇬🇧 156 522 374ms 9 Jan 2026 832nd MeWhenI 🇻🇦 155 509 37ms 2 Nov 2024 832nd CaedenHarper 🇨🇦 155 509 37ms 22 Jan 2025 832nd JOrE20 155 509 38ms 2 Feb 2026 835th KatieLG 🇬🇧 155 510 36ms 1 Nov 2024 836th KatieLG-Transpiler 🇬🇧 155 531 113ms 9 Jan 2026 837th Kokusui 🇯🇵 154 434 5ms 19 Nov 2024 838th HumanoidCPU 154 454 79ms 1 Nov 2024 838th dokutan 154 454 71ms 1 Nov 2024 838th CaedenHarper 🇨🇦 154 454 74ms 16 Aug 2025 841st snoozingnewt 🇨🇦 154 476 2,532ms 27 Sep 2025 842nd KatieLG-Transpiler 🇬🇧 154 511 36ms 9 Jan 2026 843rd HumanoidCPU 152 448 148ms 1 Nov 2024 843rd Shanethegamer 🇺🇸 152 448 139ms 1 Nov 2024 843rd MeWhenI 🇻🇦 152 448 143ms 2 Nov 2024 843rd CaedenHarper 🇨🇦 152 448 134ms 16 Aug 2025 847th Shanethegamer 🇺🇸 151 443 4ms 8 May 2025 848th Shanethegamer 🇺🇸 151 450 798ms 16 Apr 2025 848th KatieLG 🇬🇧 151 450 841ms 20 Apr 2025 848th MeWhenI 🇻🇦 151 450 839ms 15 Sep 2025 851st adamnielson42 🇺🇸 150 395 4,427ms 3 Dec 2024 852nd HumanoidCPU 150 445 4ms 1 Nov 2024 852nd MeWhenI 🇻🇦 150 445 4ms 2 Nov 2024 852nd fischfood 150 445 5ms 8 Nov 2024 852nd CaedenHarper 🇨🇦 150 445 5ms 16 Aug 2025 856th HumanoidCPU 150 448 1ms 1 Nov 2024 856th Shanethegamer 🇺🇸 150 448 1ms 1 Nov 2024 856th koipondx86 150 448 1ms 1 Nov 2024 856th MeWhenI 🇻🇦 150 448 1ms 2 Nov 2024 856th CaedenHarper 🇨🇦 150 448 1ms 16 Aug 2025 861st KatieLG-Transpiler 🇬🇧 150 578 2ms 9 Jan 2026 862nd KatieLG-Transpiler 🇬🇧 149 538 419ms 9 Jan 2026 863rd Unknownuserfrommars 149 557 3,329ms 10 Dec 2024 864th KatieLG 🇬🇧 147 563 1,373ms 1 Nov 2024 865th HumanoidCPU 146 456 1ms 1 Nov 2024 865th Shanethegamer 🇺🇸 146 456 2ms 1 Nov 2024 865th CaedenHarper 🇨🇦 146 456 1ms 23 Jan 2025 865th Maashau 146 456 2ms 12 Dec 2025 869th KatieLG 🇬🇧 146 466 158ms 30 Nov 2025 870th KatieLG 🇬🇧 146 538 491ms 1 Nov 2024 871st Maznek 144 364 10ms 8 Nov 2024 871st elisherer 🇮🇱 144 364 10ms 3 Nov 2025 873rd HumanoidCPU 144 461 112ms 1 Nov 2024 873rd KatieLG 🇬🇧 144 461 118ms 1 Nov 2024 873rd Shanethegamer 🇺🇸 144 461 123ms 1 Nov 2024 873rd MeWhenI 🇻🇦 144 461 110ms 2 Nov 2024 873rd CaedenHarper 🇨🇦 144 461 110ms 24 Jan 2025 878th dokutan 143 349 125ms 27 Dec 2025 879th KatieLG 🇬🇧 143 469 5ms 30 Nov 2025 880th KatieLG-Transpiler 🇬🇧 143 528 379ms 9 Jan 2026 First Prev 801–880 of 1,104 Next Last