The Calendar hole will go live in approximately 6 days. Why not try and solve it ahead of time?
Collatz 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 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 Chars Time Submitted 878th bac0id 845 64 5ms 29 Jun 2024 878th snoozingnewt 🇨🇦 845 64 5ms 1 Sep 2024 878th albanian-laundromat 845 64 5ms 22 Sep 2025 884th lynn 845 96 29ms 11 Jul 2023 885th Shanethegamer 🇺🇸 845 98 119ms 26 Oct 2022 885th emgordon154 845 98 121ms 18 Feb 2025 887th janAkali 🇷🇺 844 77 123ms 12 Feb 2025 888th bschorno 844 92 366ms 12 Oct 2022 888th ChrisTheisen 844 92 339ms 14 Dec 2022 888th kellantech 844 92 363ms 4 Jul 2023 888th Mezzofloat 844 92 377ms 26 Aug 2023 888th Maximizer02 844 92 360ms 1 Oct 2023 888th madeforlosers 844 92 365ms 21 Nov 2024 888th ChromaChroma 844 92 354ms 7 Oct 2025 888th snoozingnewt 🇨🇦 844 92 374ms 8 Oct 2025 896th DialFrost 🇸🇬 843 66 85ms 7 Apr 2025 896th KasperKivimaeki 🇫🇮 843 66 8ms 2 days ago 898th dokutan 843 93 428ms 27 Sep 2025 899th krcs 🇵🇱 842 53 282ms 9 May 2022 899th ryanlanegit 842 53 260ms 19 Jun 2022 899th sisyphus-ppcg 🇦🇺 842 53 402ms 15 Aug 2022 902nd MeWhenI 🇻🇦 842 71 106ms 13 Dec 2022 903rd frosster 842 80 11ms 3 hours ago 904th SirBogman 🇺🇸 842 89 38ms 4 May 2022 905th error256 841 81 68ms 13 Sep 2024 906th CLOStrophobic 🇮🇹 841 89 42ms 14 Feb 2025 907th kmathis22 841 100 31ms 13 Nov 2025 908th raszpi 🇭🇺 840 77 103ms 1 Sep 2023 909th eshilo-draper 839 75 84ms 6 Sep 2022 909th kmathis22 839 75 79ms 5 Sep 2025 911th sean-niemann 🇺🇸 839 76 107ms 8 Oct 2024 912th beardotpdf 839 99 346ms 12 days ago 913th emplv 🇱🇻 839 124 25ms 31 Oct 2022 914th Codsilla 🇨🇦 838 51 266ms 1 Jul 2022 915th frankgraziano 838 66 4ms 20 Apr 2025 916th Andriamanitra 🇫🇮 838 83 12ms 17 Apr 2023 916th Natanaelel 🇸🇪 838 83 12ms 8 Jul 2023 918th MeWhenI 🇻🇦 838 164 1,639ms 7 Nov 2025 919th ovs-code 🇩🇪 837 85 15ms 11 Dec 2023 920th dokutan 837 88 39ms 9 Jun 2024 921st Steffan153 🇫🇮 837 97 29ms 18 Jan 2023 922nd CatsAreFluffy 837 101 54ms 18 Feb 2023 922nd annaproxy 837 101 59ms 9 May 2023 922nd wojtekmal 837 101 61ms 15 Nov 2023 922nd HumanoidCPU 837 101 60ms 6 May 2024 922nd eMGeeneer 837 101 412ms 27 Jun 2024 922nd bac0id 837 101 60ms 29 Jun 2024 922nd michaelmoynihan 837 101 413ms 3 Sep 2025 922nd snoozingnewt 🇨🇦 837 101 421ms 6 Oct 2025 930th SirBogman 🇺🇸 835 36 14ms 5 May 2022 930th Natanaelel 🇸🇪 835 36 87ms 15 Jun 2022 930th Steffan153 🇫🇮 835 36 91ms 18 Jan 2023 930th codereport 🇨🇦 835 36 9ms 1 Jun 2024 930th GolfinK 835 36 9ms 21 Nov 2024 930th lifthrasiir 🇰🇷 835 36 10ms 1 Dec 2024 930th GolfingSuccess 🇬🇷 835 36 11ms 20 Mar 2025 937th scpchicken 🇵🇼 835 55 10ms 4 May 2022 937th SirBogman 🇺🇸 835 55 6ms 5 May 2022 937th Shanethegamer 🇺🇸 835 55 6ms 19 May 2023 937th DialFrost 🇸🇬 835 55 10ms 14 Feb 2025 941st ChiefChippy2 835 56 38ms 4 May 2022 941st aksyristos 835 56 37ms 29 Jan 2023 941st anter69 🇭🇺 835 56 38ms 12 Feb 2024 941st 3dm4n 🇫🇮 835 56 37ms 11 Mar 2024 941st lgrandco 835 56 41ms 9 Oct 2024 941st tatzyr 🇯🇵 835 56 43ms 10 Dec 2024 941st D-MOVE 🇵🇭 835 56 42ms 16 days ago 948th inverseLorentz 🇦🇺 835 69 156ms 3 Jun 2024 948th Yewzir 🇧🇪 835 69 118ms 24 Dec 2024 948th CLOStrophobic 🇮🇹 835 69 170ms 28 May 2025 951st p-vf 🇨🇭 835 93 337ms 24 Jun 2022 951st Smetalo 835 93 384ms 25 Aug 2022 951st malworthy 835 93 360ms 19 Aug 2024 954th moustave 834 67 23ms 7 Nov 2024 955th Alex-x90 🇺🇸 834 74 2ms 4 Dec 2022 955th undersquire 834 74 2ms 24 Jun 2023 955th rdmsr 834 74 2ms 24 Jun 2023 955th Bmrl7 834 74 2ms 9 Jul 2023 955th Vinterion 834 74 4ms 6 Nov 2023 955th namelessiw 834 74 2ms 28 Dec 2023 First Prev 881–960 of 3,480 Next Last