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?
Collatz 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 386th acollett89 907 59 12ms 17 Jun 2025 386th iczelia 🇩🇪 907 59 12ms 23 Sep 2025 386th Yax42 🇫🇷 907 59 10ms 20 Jan 2026 386th Protothor 907 59 11ms 9 hours ago 405th Steffan153 🇫🇮 907 80 28ms 15 Nov 2022 405th error256 907 80 117ms 8 Apr 2025 407th nipzu 906 48 46ms 8 Sep 2024 408th shinh 906 52 43ms 29 Jun 2022 409th Lydxn 🇨🇦 906 64 181ms 1 Apr 2023 410th krcs 🇵🇱 906 86 381ms 10 May 2022 410th billings7 🇬🇧 906 86 384ms 15 May 2022 410th revlayle 🇺🇸 906 86 379ms 7 Dec 2022 410th Widgitty 906 86 368ms 1 Sep 2023 410th albanian-laundromat 906 86 430ms 30 Sep 2025 415th piano-miles 906 92 411ms 24 Feb 2026 416th Lydxn 🇨🇦 905 70 96ms 7 May 2022 417th MeWhenI 🇻🇦 905 71 148ms 20 Aug 2024 418th m-tkach 🇺🇦 904 72 110ms 16 Oct 2022 418th GrayJoKing 🇦🇺 904 72 113ms 22 Oct 2022 418th emplv 🇱🇻 904 72 111ms 27 Oct 2022 418th sean-niemann 🇺🇸 904 72 172ms 7 Mar 2025 422nd DialFrost 🇸🇬 904 74 17ms 22 Feb 2026 422nd Steffan153 🇫🇮 904 74 17ms 22 Feb 2026 422nd GrayJoKing 🇦🇺 904 74 16ms 22 Feb 2026 422nd GolfingSuccess 🇬🇷 904 74 17ms 24 Feb 2026 422nd snoozingnewt 🇨🇦 904 74 16ms 23 days ago 422nd edsrzf 🇳🇿 904 74 16ms 17 days ago 428th Steffan153 🇫🇮 904 82 42ms 1 Apr 2023 428th sean-niemann 🇺🇸 904 82 42ms 12 Jul 2024 430th stefangimmillaro 904 92 130ms 24 Oct 2023 430th inverseLorentz 🇦🇺 904 92 120ms 27 May 2024 430th sean-niemann 🇺🇸 904 92 129ms 8 Jun 2025 430th ian-h-chamberlain 🇺🇸 904 92 146ms 23 Nov 2025 434th michael-pruglo 🇺🇦 904 94 61ms 5 Jul 2022 434th zygoloid 904 94 60ms 5 Aug 2024 434th AdrienHache 🇫🇷 904 94 60ms 27 Dec 2025 437th Lydxn 🇨🇦 902 69 6ms 12 Sep 2022 437th GrayJoKing 🇦🇺 902 69 7ms 12 Sep 2022 437th btnlq 902 69 7ms 24 Sep 2022 440th albanian-laundromat 901 107 274ms 22 Dec 2025 441st SirBogman 🇺🇸 900 50 516ms 5 May 2022 441st nwellnhof 🇩🇪 900 50 504ms 3 Jun 2022 441st Lydxn 🇨🇦 900 50 431ms 15 Aug 2022 441st Steffan153 🇫🇮 900 50 485ms 9 Aug 2024 445th Steffan153 🇫🇮 900 67 112ms 18 Dec 2022 445th Lydxn 🇨🇦 900 67 122ms 4 Feb 2023 445th sean-niemann 🇺🇸 900 67 110ms 7 Mar 2025 448th Lydxn 🇨🇦 900 72 353ms 16 Jul 2023 449th GrayJoKing 🇦🇺 899 70 2ms 6 May 2022 449th saito-ta 🇯🇵 899 70 2ms 21 Dec 2023 449th ovs-code 🇩🇪 899 70 2ms 17 Feb 2024 449th trinityy-7 899 70 2ms 7 Aug 2025 449th KasperKivimaeki 🇫🇮 899 70 6ms 8 Aug 2025 454th GrayJoKing 🇦🇺 899 91 30ms 19 Jan 2023 455th Lydxn 🇨🇦 898 48 257ms 5 May 2022 455th p-zubieta 898 48 299ms 6 Mar 2024 457th NickTheEASDude 🇺🇸 898 76 6ms 7 May 2024 457th edsrzf 🇳🇿 898 76 6ms 23 Dec 2025 457th Shanethegamer 🇺🇸 898 76 5ms 23 Dec 2025 457th jared-hughes 898 76 5ms 24 Dec 2025 457th Waffle3z 898 76 5ms 26 Dec 2025 457th Blendi-Goose 898 76 5ms 6 Feb 2026 457th kTheLemon 898 76 5ms 19 days ago 464th edsrzf 🇳🇿 898 78 12ms 26 Oct 2024 465th DialFrost 🇸🇬 897 29 154ms 15 Mar 2025 466th Steffan153 🇫🇮 897 59 156ms 10 Aug 2024 466th rucin93 🇵🇱 897 59 144ms 13 Oct 2024 466th sean-niemann 🇺🇸 897 59 147ms 13 Oct 2024 466th lukegustafson 🇺🇸 897 59 140ms 24 Oct 2024 470th Ripick 897 73 122ms 8 May 2023 471st ovs-code 🇩🇪 897 89 458ms 24 Jul 2024 471st jipsong 🇩🇪 897 89 450ms 7 Apr 2025 471st DialFrost 🇸🇬 897 89 485ms 24 Dec 2025 471st dokutan 897 89 425ms 8 Feb 2026 475th nwellnhof 🇩🇪 896 69 24ms 4 May 2022 475th m-tkach 🇺🇦 896 69 18ms 4 May 2022 475th GolfingSuccess 🇬🇷 896 69 17ms 5 May 2022 475th jared-hughes 896 69 17ms 5 May 2022 475th ovs-code 🇩🇪 896 69 23ms 5 May 2022 475th btnlq 896 69 17ms 5 May 2022 First Prev 401–480 of 3,645 Next Last