The Calendar hole will go live in approximately 10 days. Why not try and solve it ahead of time?
PalindromemordnilaP 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 559th NickTheEASDude 🇺🇸 600 104 10ms 7 Oct 2025 562nd Shanethegamer 🇺🇸 600 134 412ms 1 Sep 2024 563rd inventshah 599 150 2ms 1 Sep 2024 564th Shanethegamer 🇺🇸 595 177 51ms 4 Sep 2024 565th mousetail 🇳🇱 594 105 6ms 3 Sep 2024 566th BREMAUCY 🇫🇷 594 316 12ms 7 Aug 2025 567th KatieLG 🇬🇧 593 77 790ms 1 Sep 2024 568th CaedenHarper 🇨🇦 593 149 392ms 16 Oct 2025 569th h3ra993huskp 🇯🇵 592 163 687ms 21 days ago 570th CutSandstone 589 106 13ms 21 Dec 2024 571st KatieLG 🇬🇧 589 135 94ms 21 Nov 2025 572nd luuumine 🇫🇷 586 204 194ms 18 Nov 2025 573rd Shanethegamer 🇺🇸 584 120 6ms 2 Sep 2024 574th cbrt-x 584 151 121ms 11 Sep 2024 575th DialFrost 🇸🇬 583 107 7ms 1 Sep 2024 575th galloj 🇨🇿 583 107 10ms 4 Sep 2024 575th jared-hughes 583 107 10ms 10 Sep 2024 575th nstearns96 🇬🇧 583 107 10ms 13 Nov 2024 575th brochmann 🇸🇪 583 107 10ms 16 Oct 2025 580th Upload-and-View 🇺🇦 580 119 2ms 23 Jul 2025 581st GeorgeStechman 🇬🇧 580 122 10ms 5 Nov 2024 581st gigaprofisi 🇺🇸 580 122 9ms 10 Aug 2025 583rd snoozingnewt 🇨🇦 580 226 251ms 1 Sep 2024 584th JesseNoEyes 🇺🇸 578 108 9ms 30 Sep 2024 585th JohandeRuiter 🇳🇱 576 156 2ms 2 Sep 2024 586th RedzGoose 🇦🇺 575 101 475ms 15 Oct 2024 587th xyangst 575 123 9ms 15 Oct 2024 588th Mabeloid 🇳🇴 573 109 10ms 1 Sep 2024 588th MassimoParisi 573 109 11ms 18 Sep 2024 588th klixel 🇨🇦 573 109 10ms 21 Sep 2024 588th NotNoper 573 109 9ms 29 Oct 2024 588th za3k 573 109 11ms 15 Jul 2025 593rd vhoulbreque 🇫🇷 573 146 201ms 11 Nov 2025 594th TeodorDyakov 🇧🇬 565 159 2ms 6 Sep 2025 595th aksyristos 562 111 11ms 1 Sep 2024 595th AstroOrbis 562 111 10ms 30 Jun 2025 597th tomh1012 562 126 9ms 18 Sep 2025 598th MostParsingVex 562 160 33ms 30 Sep 2024 599th dokutan 561 132 3ms 1 Sep 2024 600th emgordon154 559 138 11ms 1 Jan 2025 601st RedzGoose 🇦🇺 553 145 116ms 9 Sep 2024 602nd msbranicky 548 135 3ms 1 Sep 2024 603rd HumanoidCPU 547 110 143ms 22 Nov 2025 604th Yewzir 🇧🇪 543 115 11ms 20 days ago 605th KatieLG 🇬🇧 539 128 2ms 2 Oct 2025 606th dokutan 539 155 242ms 1 Sep 2024 607th Shanethegamer 🇺🇸 538 107 91ms 1 Sep 2024 608th LeoCh01 538 116 9ms 1 Sep 2024 609th Shanethegamer 🇺🇸 536 91 25ms 1 Sep 2024 610th snoozingnewt 🇨🇦 534 79 40ms 12 Oct 2025 611th Mabeloid 🇳🇴 533 109 701ms 17 Sep 2024 612th albanian-laundromat 533 352 11ms 18 Sep 2025 613th trijin 529 118 5ms 5 Oct 2024 614th Shanethegamer 🇺🇸 528 183 452ms 24 Sep 2025 615th emgordon154 527 133 15ms 16 Dec 2024 616th Zhenyu-Bo 524 119 11ms 1 Aug 2025 617th tomh1012 523 169 395ms 17 Sep 2025 618th lhulinsky 520 120 11ms 23 Oct 2024 618th arjunarya1 520 120 10ms 11 Sep 2025 620th ravnskjaer 🇩🇰 519 186 344ms 6 days ago 621st error256 515 134 2ms 24 Sep 2024 622nd CaedenHarper 🇨🇦 514 188 438ms 3 Oct 2025 623rd kevinnaviapaiva 512 122 12ms 16 Feb 2025 624th Shanethegamer 🇺🇸 512 141 105ms 17 days ago 625th eddvrs 507 123 11ms 29 Sep 2024 626th Yewzir 🇧🇪 505 115 364ms 20 days ago 627th yokasuretsu 503 124 11ms 10 Jul 2025 627th hamilton-bonds 503 124 10ms 24 Jul 2025 629th madex 🇩🇪 502 84 45ms 1 Sep 2024 630th dbut2 🇦🇺 502 261 254ms 3 Sep 2024 631st LukeBridges 🇬🇧 498 142 9ms 3 Sep 2024 632nd snoozingnewt 🇨🇦 497 160 101ms 1 Sep 2024 633rd MeWhenI 🇻🇦 497 181 2ms 13 Jun 2025 634th nhausspiegel 495 126 10ms 13 Sep 2024 635th matsagad 491 127 10ms 16 Jan 2025 636th madex 🇩🇪 491 183 2ms 2 Sep 2024 637th xyangst 488 128 11ms 12 Oct 2024 637th 123mjb 488 128 10ms 19 Nov 2025 639th alphafalfa 480 105 4ms 1 Nov 2024 640th snoozingnewt 🇨🇦 480 120 118ms 14 Oct 2025 First Prev 561–640 of 711 Next Last