The Calendar hole will go live in approximately 8 days. Why not try and solve it 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 Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz 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 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 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> 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 ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> 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 ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight 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 Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz 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 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 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Bytes Time Submitted 321st kmathis22 916 91 548ms 20 Nov 2025 322nd Natanaelel 🇸🇪 915 57 417ms 17 Jan 2024 322nd Kacarott 🇦🇺 915 57 394ms 10 Sep 2024 324th Shanethegamer 🇺🇸 915 61 3ms 9 Oct 2023 324th edsrzf 🇳🇿 915 61 3ms 4 Jul 2025 326th ovs-code 🇩🇪 915 75 78ms 12 Sep 2024 326th Kacarott 🇦🇺 915 75 62ms 13 Sep 2024 328th Lydxn 🇨🇦 915 81 39ms 1 Apr 2023 329th andersk 🇺🇸 914 91 124ms 25 Oct 2022 329th Super-Pizza 🇨🇦 914 91 124ms 4 Dec 2022 329th klixel 🇨🇦 914 91 125ms 20 May 2023 329th lynn 914 91 122ms 6 Jul 2024 329th edsrzf 🇳🇿 914 91 125ms 29 Nov 2024 329th DialFrost 🇸🇬 914 91 136ms 7 Apr 2025 335th lynn 913 78 1,300ms 5 May 2022 336th GrayJoKing 🇦🇺 912 71 321ms 10 Aug 2023 337th tailorspy 912 93 84ms 27 May 2024 337th sean-niemann 🇺🇸 912 93 81ms 9 Jun 2025 337th KasperKivimaeki 🇫🇮 912 93 56ms 26 Oct 2025 340th nai62 911 69 7ms 27 Aug 2022 341st GolfingSuccess 🇬🇷 910 64 91ms 14 Dec 2024 341st MeWhenI 🇻🇦 910 64 91ms 24 Dec 2024 341st GrayJoKing 🇦🇺 910 64 92ms 27 days ago 344th edsrzf 🇳🇿 910 72 160ms 3 Jul 2025 345th Shanethegamer 🇺🇸 910 77 13ms 15 May 2023 346th primo-ppcg 🇹🇭 910 93 30ms 7 May 2022 346th AlephSquirrel 910 93 26ms 21 Jan 2023 346th kg583 🇺🇸 910 93 29ms 26 Dec 2024 346th CLOStrophobic 🇮🇹 910 93 30ms 17 Jan 2025 346th edsrzf 🇳🇿 910 93 30ms 3 Jul 2025 351st Betuaredead 909 60 5ms 5 Jan 2023 351st Yewzir 🇧🇪 909 60 5ms 12 Feb 2023 351st Steffan153 🇫🇮 909 60 5ms 23 Feb 2023 351st DialFrost 🇸🇬 909 60 5ms 30 Jul 2024 351st GolfingSuccess 🇬🇷 909 60 5ms 16 Oct 2024 351st sean-niemann 🇺🇸 909 60 9ms 7 Mar 2025 357th MeWhenI 🇻🇦 909 63 184ms 5 May 2022 358th Lydxn 🇨🇦 909 68 464ms 5 May 2022 358th GrayJoKing 🇦🇺 909 68 15ms 15 Nov 2022 358th Bubbler-4 909 68 15ms 15 Nov 2022 358th Rubiksmath 909 68 14ms 14 Aug 2023 362nd marshallward 🇺🇸 909 83 41ms 10 May 2022 363rd ovs-code 🇩🇪 909 84 63ms 25 Sep 2022 363rd GrayJoKing 🇦🇺 909 84 66ms 11 Aug 2023 363rd edsrzf 🇳🇿 909 84 78ms 12 Nov 2025 366th DialFrost 🇸🇬 908 76 154ms 3 Aug 2025 367th edsrzf 🇳🇿 908 83 43ms 14 Jan 2025 367th kg583 🇺🇸 908 83 42ms 14 Feb 2025 369th m-tkach 🇺🇦 908 90 30ms 7 Dec 2023 370th KrausRaus 🇺🇸 907 59 10ms 4 May 2022 370th voytxt 🇨🇿 907 59 9ms 4 May 2022 370th KingSkyrock 🇺🇸 907 59 9ms 18 May 2022 370th ZakkkkAttackkkk 🇵🇭 907 59 9ms 14 Jul 2022 370th aksyristos 907 59 11ms 28 Oct 2022 370th nstearns96 🇬🇧 907 59 10ms 28 Nov 2022 370th janbehrens 🇩🇪 907 59 9ms 17 May 2023 370th Shanethegamer 🇺🇸 907 59 10ms 25 May 2023 370th Maznek 907 59 10ms 26 Jun 2023 370th SpiritAxolotl 🇺🇸 907 59 10ms 20 Mar 2024 370th Andrey-Plotnikov 907 59 9ms 19 May 2024 370th emgordon154 907 59 10ms 5 Aug 2024 370th duckyluuk 🇳🇱 907 59 10ms 3 Oct 2024 370th lifthrasiir 🇰🇷 907 59 10ms 23 Nov 2024 370th fuzzylojik-golf 🇺🇸 907 59 10ms 1 Jun 2025 370th acollett89 907 59 10ms 17 Jun 2025 370th iczelia 🇩🇪 907 59 10ms 23 Sep 2025 387th nipzu 906 48 48ms 8 Sep 2024 388th Steffan153 🇫🇮 906 80 26ms 15 Nov 2022 388th error256 906 80 115ms 8 Apr 2025 390th Shanethegamer 🇺🇸 906 82 17ms 19 Dec 2023 390th edsrzf 🇳🇿 906 82 17ms 6 Jan 2025 392nd krcs 🇵🇱 906 86 372ms 10 May 2022 392nd billings7 🇬🇧 906 86 347ms 15 May 2022 392nd revlayle 🇺🇸 906 86 337ms 7 Dec 2022 392nd Widgitty 906 86 319ms 1 Sep 2023 392nd albanian-laundromat 906 86 383ms 30 Sep 2025 397th shinh 905 52 38ms 29 Jun 2022 398th Lydxn 🇨🇦 905 64 181ms 1 Apr 2023 399th Lydxn 🇨🇦 905 70 91ms 7 May 2022 400th MeWhenI 🇻🇦 905 71 102ms 20 Aug 2024 First Prev 321–400 of 3,497 Next Last