The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 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 798th olleicua 🇺🇸 872 54 44ms 21 Jan 2024 798th LostSyntax21 🇬🇧 872 54 41ms 12 Mar 2025 798th AbrahamJLR 🇻🇪 872 54 40ms 4 Jun 2025 798th vishal-mohanty 872 54 39ms 25 Aug 2025 805th Shanethegamer 🇺🇸 872 85 38ms 15 May 2023 805th albanian-laundromat 872 85 40ms 25 Aug 2025 807th dieggsy 872 97 28ms 8 Oct 2024 808th ulucs 871 35 9ms 8 May 2022 808th bstrat 871 35 9ms 6 Jun 2024 808th wh3n3v3r 🇨🇿 871 35 8ms 18 Nov 2024 811th scpchicken 🇵🇼 871 45 358ms 4 May 2022 811th SirBogman 🇺🇸 871 45 227ms 5 May 2022 813th TFeld00 🇩🇰 871 71 25ms 17 May 2022 813th DialFrost 🇸🇬 871 71 25ms 15 Nov 2022 813th StefanHabel 🇨🇦 871 71 18ms 29 Nov 2022 813th nstearns96 🇬🇧 871 71 21ms 11 Jan 2023 813th hallvabo 🇳🇴 871 71 19ms 7 Feb 2023 813th anter69 🇭🇺 871 71 18ms 21 May 2024 813th rucin93 🇵🇱 871 71 17ms 10 Jul 2024 813th lelbal 871 71 20ms 26 Aug 2025 813th HETHAT 🇩🇿 871 71 23ms 23 Sep 2025 813th 09cf 871 71 18ms 18 Nov 2025 813th CommandLeo 🇮🇹 871 71 23ms 8 Jan 2026 813th Flekay 🇩🇪 871 71 17ms 12 Feb 2026 813th snoozingnewt 🇨🇦 871 71 18ms 13 Feb 2026 813th JOrE20 871 71 16ms 25 Feb 2026 827th ovs-code 🇩🇪 871 133 42ms 8 Jul 2024 828th emgordon154 870 160 1,606ms 24 Dec 2025 828th DialFrost 🇸🇬 870 160 1,779ms 17 Jan 2026 830th Steffan153 🇫🇮 869 82 1,323ms 23 Feb 2023 831st 123mjb 869 96 366ms 20 Nov 2025 831st noescareno 869 96 366ms 21 Nov 2025 833rd Frowny 868 38 40ms 5 May 2022 833rd stackofbears 868 38 42ms 14 Mar 2025 835th steffan-polygolf 868 73 88ms 23 Feb 2023 835th MWI-polygolf 868 73 84ms 6 Dec 2023 835th HumanoidCPU 868 73 82ms 7 May 2024 838th nwellnhof 🇩🇪 868 111 301ms 4 May 2022 838th emplv 🇱🇻 868 111 294ms 5 May 2022 838th Shanethegamer 🇺🇸 868 111 293ms 21 Nov 2023 841st pardouin 🇫🇷 867 61 156ms 7 Aug 2024 842nd MeWhenI 🇻🇦 867 92 467ms 10 Oct 2022 842nd Betuaredead 867 92 480ms 5 Jan 2023 842nd Yax42 🇫🇷 867 92 470ms 4 Oct 2025 845th shellbertt 🇨🇦 867 98 61ms 9 May 2022 845th iakolzin 867 98 58ms 26 May 2022 845th Betuaredead 867 98 62ms 5 Jan 2023 845th oceko 867 98 60ms 19 Feb 2024 845th cuzdav 867 98 60ms 4 May 2025 845th timhaj 🇸🇮 867 98 60ms 12 Sep 2025 845th Yax42 🇫🇷 867 98 61ms 4 Oct 2025 852nd 5quiwyrm 866 52 304ms 4 Sep 2022 852nd MeWhenI 🇻🇦 866 52 318ms 28 Jan 2023 852nd Feniske 🇫🇷 866 52 317ms 7 Nov 2023 852nd dcgjb 866 52 279ms 29 Jan 2024 852nd JPRuskin 🇬🇧 866 52 314ms 7 Apr 2025 852nd IISResetMe 866 52 325ms 7 Apr 2025 852nd Ripick 866 52 315ms 1 Jun 2025 852nd madex 🇩🇪 866 52 363ms 8 days ago 860th bac0id 866 90 354ms 26 Sep 2023 860th deadp4nda 🇩🇪 866 90 374ms 26 Apr 2024 860th 123mjb 866 90 367ms 23 Jun 2025 860th michelebastione 🇮🇹 866 90 400ms 24 Aug 2025 860th razvandmtr 🇷🇴 866 90 395ms 6 Nov 2025 865th TylerBloom 866 96 125ms 22 Mar 2024 866th Andriamanitra 🇫🇮 865 67 144ms 26 Apr 2023 867th MeWhenI 🇻🇦 865 81 8ms 23 May 2023 868th typeswitch-dev 🇵🇹 864 75 5ms 22 Jul 2023 869th dokutan 864 79 10ms 27 Apr 2024 869th SwordF-Official 🇺🇸 864 79 10ms 1 Feb 2026 871st DialFrost 🇸🇬 864 84 17ms 1 Jan 2026 872nd ovs-code 🇩🇪 864 161 1,719ms 14 Sep 2025 872nd Yewzir 🇧🇪 864 161 1,887ms 14 Nov 2025 874th HPWiz 🇳🇿 863 50 265ms 4 May 2022 874th JayXon 🇺🇸 863 50 250ms 5 May 2022 874th Steffan153 🇫🇮 863 50 256ms 10 Dec 2022 874th ovs-code 🇩🇪 863 50 403ms 24 Oct 2023 874th sean-niemann 🇺🇸 863 50 268ms 12 Jul 2024 879th Setvizan 863 62 13ms 12 Jan 2023 879th GreenBeansAgainstVeganism 863 62 11ms 13 Jan 2023 First Prev 801–880 of 3,645 Next Last