The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 7 days. Why not try and solve them ahead of time?
Kaprekar Numbers in all languages in bytes. 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 Bytes Time Submitted 795th KatieLG-Transpiler 🇬🇧 165 441 3ms 9 Jan 2026 802nd dokutan 165 445 2,473ms 1 Nov 2024 802nd MeWhenI 🇻🇦 165 445 2,374ms 2 Nov 2024 802nd CaedenHarper 🇨🇦 165 445 2,340ms 1 Feb 2025 805th HumanoidCPU 165 458 404ms 1 Nov 2024 805th Shanethegamer 🇺🇸 165 458 402ms 1 Nov 2024 805th dokutan 165 458 401ms 1 Nov 2024 805th mwarvik 🇳🇴 165 458 417ms 5 Jan 2026 809th HumanoidCPU 162 452 2,438ms 1 Nov 2024 809th Shanethegamer 🇺🇸 162 452 2,490ms 1 Nov 2024 811th HumanoidCPU 160 657 30ms 4 Nov 2025 812th dokutan 159 318 53ms 1 Nov 2024 813th CaedenHarper 🇨🇦 159 659 26ms 16 Aug 2025 814th KatieLG-Transpiler 🇬🇧 159 660 26ms 9 Jan 2026 815th KatieLG-Transpiler 🇬🇧 156 522 374ms 9 Jan 2026 816th dokutan 155 349 125ms 27 Dec 2025 817th dokutan 155 509 37ms 1 Nov 2024 817th MeWhenI 🇻🇦 155 509 37ms 2 Nov 2024 817th CaedenHarper 🇨🇦 155 509 37ms 22 Jan 2025 817th JOrE20 155 509 38ms 2 Feb 2026 821st KatieLG 🇬🇧 155 510 36ms 1 Nov 2024 822nd KatieLG-Transpiler 🇬🇧 155 531 106ms 9 Jan 2026 823rd Kokusui 🇯🇵 154 434 5ms 19 Nov 2024 824th HumanoidCPU 154 454 64ms 1 Nov 2024 824th dokutan 154 454 64ms 1 Nov 2024 824th CaedenHarper 🇨🇦 154 454 67ms 16 Aug 2025 827th snoozingnewt 🇨🇦 154 476 2,532ms 27 Sep 2025 828th KatieLG-Transpiler 🇬🇧 154 511 36ms 9 Jan 2026 829th denkyuu1 153 346 34ms 18 days ago 830th JunkIce 153 449 9ms 21 Nov 2024 831st HumanoidCPU 152 448 148ms 1 Nov 2024 831st dokutan 152 448 144ms 1 Nov 2024 831st Shanethegamer 🇺🇸 152 448 139ms 1 Nov 2024 831st MeWhenI 🇻🇦 152 448 143ms 2 Nov 2024 831st CaedenHarper 🇨🇦 152 448 134ms 16 Aug 2025 836th HumanoidCPU 152 452 10ms 1 Nov 2024 836th GolfingSuccess 🇬🇷 152 452 10ms 1 Nov 2024 836th zbreit 🇺🇸 152 452 10ms 1 Nov 2024 836th Shanethegamer 🇺🇸 152 452 10ms 1 Nov 2024 836th madex 🇩🇪 152 452 10ms 1 Nov 2024 836th jtaxen 152 452 10ms 1 Nov 2024 836th Stockoh 🇫🇷 152 452 9ms 4 Nov 2024 836th evan18c 152 452 10ms 7 Nov 2024 836th roguh 🇬🇹 152 452 9ms 27 Nov 2024 836th mathisfun271 152 452 10ms 25 Jan 2025 836th moustave 152 452 10ms 9 Apr 2025 836th SectorCorruptor 152 452 10ms 24 Jul 2025 836th vgamula 🇺🇦 152 452 11ms 25 Jul 2025 836th Unknownuserfrommars 152 452 10ms 5 Aug 2025 836th JOrE20 152 452 10ms 6 Nov 2025 836th TheSecondComing123 152 452 10ms 26 days ago 852nd Shanethegamer 🇺🇸 151 443 4ms 8 May 2025 853rd Shanethegamer 🇺🇸 151 450 798ms 16 Apr 2025 853rd KatieLG 🇬🇧 151 450 841ms 20 Apr 2025 853rd dokutan 151 450 877ms 23 Jul 2025 853rd HumanoidCPU 151 450 820ms 18 Aug 2025 853rd MeWhenI 🇻🇦 151 450 839ms 15 Sep 2025 858th HumanoidCPU 150 445 4ms 1 Nov 2024 858th dokutan 150 445 4ms 1 Nov 2024 858th MeWhenI 🇻🇦 150 445 4ms 2 Nov 2024 858th fischfood 150 445 5ms 8 Nov 2024 858th CaedenHarper 🇨🇦 150 445 5ms 16 Aug 2025 863rd HumanoidCPU 150 448 1ms 1 Nov 2024 863rd Shanethegamer 🇺🇸 150 448 1ms 1 Nov 2024 863rd koipondx86 150 448 1ms 1 Nov 2024 863rd MeWhenI 🇻🇦 150 448 1ms 2 Nov 2024 863rd CaedenHarper 🇨🇦 150 448 1ms 16 Aug 2025 868th KasperKivimaeki 🇫🇮 150 457 10ms 15 Jul 2025 869th muser-logiccpu 🇺🇦 150 458 9ms 9 Aug 2025 869th netfri25 🇮🇱 150 458 10ms 21 Feb 2026 869th rotemkm 150 458 10ms 21 Feb 2026 872nd KatieLG-Transpiler 🇬🇧 149 538 419ms 9 Jan 2026 873rd Unknownuserfrommars 149 557 3,414ms 10 Dec 2024 874th HumanoidCPU 148 456 1ms 1 Nov 2024 874th dokutan 148 456 1ms 1 Nov 2024 874th Shanethegamer 🇺🇸 148 456 2ms 1 Nov 2024 874th CaedenHarper 🇨🇦 148 456 1ms 23 Jan 2025 874th Maashau 148 456 2ms 12 Dec 2025 879th KatieLG 🇬🇧 147 563 1,376ms 1 Nov 2024 880th KatieLG 🇬🇧 146 466 158ms 30 Nov 2025 First Prev 801–880 of 1,110 Next Last