The Calendar hole will go live in approximately 12 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 561st mousetail 🇳🇱 594 105 6ms 3 Sep 2024 562nd BREMAUCY 🇫🇷 594 316 12ms 7 Aug 2025 563rd KatieLG 🇬🇧 593 77 790ms 1 Sep 2024 564th CaedenHarper 🇨🇦 593 149 392ms 16 Oct 2025 565th h3ra993huskp 🇯🇵 592 163 687ms 19 days ago 566th CutSandstone 589 106 13ms 21 Dec 2024 567th KatieLG 🇬🇧 589 135 94ms 27 days ago 568th luuumine 🇫🇷 586 204 194ms 18 Nov 2025 569th Shanethegamer 🇺🇸 584 120 6ms 2 Sep 2024 570th DialFrost 🇸🇬 583 107 7ms 1 Sep 2024 570th galloj 🇨🇿 583 107 10ms 4 Sep 2024 570th jared-hughes 583 107 10ms 10 Sep 2024 570th nstearns96 🇬🇧 583 107 10ms 13 Nov 2024 570th brochmann 🇸🇪 583 107 10ms 16 Oct 2025 575th cbrt-x 583 151 121ms 11 Sep 2024 576th Upload-and-View 🇺🇦 580 119 2ms 23 Jul 2025 577th GeorgeStechman 🇬🇧 580 122 10ms 5 Nov 2024 577th gigaprofisi 🇺🇸 580 122 9ms 10 Aug 2025 579th snoozingnewt 🇨🇦 580 226 251ms 1 Sep 2024 580th JesseNoEyes 🇺🇸 578 108 9ms 30 Sep 2024 581st JohandeRuiter 🇳🇱 576 156 2ms 2 Sep 2024 582nd RedzGoose 🇦🇺 575 101 475ms 15 Oct 2024 583rd xyangst 575 123 9ms 15 Oct 2024 584th Mabeloid 🇳🇴 573 109 10ms 1 Sep 2024 584th MassimoParisi 573 109 11ms 18 Sep 2024 584th klixel 🇨🇦 573 109 10ms 21 Sep 2024 584th NotNoper 573 109 9ms 29 Oct 2024 584th za3k 573 109 11ms 15 Jul 2025 589th vhoulbreque 🇫🇷 573 146 201ms 11 Nov 2025 590th TeodorDyakov 🇧🇬 565 159 2ms 6 Sep 2025 591st aksyristos 562 111 11ms 1 Sep 2024 591st AstroOrbis 562 111 10ms 30 Jun 2025 593rd tomh1012 562 126 9ms 18 Sep 2025 594th MostParsingVex 562 160 33ms 30 Sep 2024 595th dokutan 561 132 3ms 1 Sep 2024 596th emgordon154 559 138 11ms 1 Jan 2025 597th RedzGoose 🇦🇺 553 145 116ms 9 Sep 2024 598th msbranicky 548 135 3ms 1 Sep 2024 599th HumanoidCPU 547 110 143ms 27 days ago 600th Yewzir 🇧🇪 543 115 11ms 18 days ago 601st KatieLG 🇬🇧 539 128 2ms 2 Oct 2025 602nd dokutan 539 155 242ms 1 Sep 2024 603rd Shanethegamer 🇺🇸 538 107 91ms 1 Sep 2024 604th LeoCh01 538 116 9ms 1 Sep 2024 605th Shanethegamer 🇺🇸 535 91 25ms 1 Sep 2024 606th snoozingnewt 🇨🇦 534 79 40ms 12 Oct 2025 607th Mabeloid 🇳🇴 533 109 701ms 17 Sep 2024 608th albanian-laundromat 533 352 11ms 18 Sep 2025 609th trijin 529 118 5ms 5 Oct 2024 610th Shanethegamer 🇺🇸 528 183 452ms 24 Sep 2025 611th emgordon154 527 133 15ms 16 Dec 2024 612th Zhenyu-Bo 524 119 11ms 1 Aug 2025 613th tomh1012 523 169 395ms 17 Sep 2025 614th lhulinsky 520 120 11ms 23 Oct 2024 614th arjunarya1 520 120 10ms 11 Sep 2025 616th ravnskjaer 🇩🇰 519 186 344ms 4 days ago 617th error256 515 134 2ms 24 Sep 2024 618th CaedenHarper 🇨🇦 514 188 438ms 3 Oct 2025 619th kevinnaviapaiva 512 122 12ms 16 Feb 2025 620th Shanethegamer 🇺🇸 512 141 105ms 15 days ago 621st eddvrs 507 123 11ms 29 Sep 2024 622nd Yewzir 🇧🇪 505 115 364ms 18 days ago 623rd yokasuretsu 503 124 11ms 10 Jul 2025 623rd hamilton-bonds 503 124 10ms 24 Jul 2025 625th madex 🇩🇪 502 84 45ms 1 Sep 2024 626th dbut2 🇦🇺 502 261 254ms 3 Sep 2024 627th LukeBridges 🇬🇧 498 142 9ms 3 Sep 2024 628th snoozingnewt 🇨🇦 497 160 101ms 1 Sep 2024 629th MeWhenI 🇻🇦 497 181 2ms 13 Jun 2025 630th nhausspiegel 495 126 10ms 13 Sep 2024 631st matsagad 491 127 10ms 16 Jan 2025 632nd madex 🇩🇪 491 183 2ms 2 Sep 2024 633rd xyangst 488 128 11ms 12 Oct 2024 633rd 123mjb 488 128 10ms 19 Nov 2025 635th alphafalfa 480 105 4ms 1 Nov 2024 636th snoozingnewt 🇨🇦 480 120 118ms 14 Oct 2025 637th snoozingnewt 🇨🇦 478 185 387ms 4 Oct 2025 638th snoozingnewt 🇨🇦 476 189 5ms 9 Oct 2025 639th rucin93 🇵🇱 476 251 221ms 5 Sep 2024 640th junkondo-jp 475 149 9ms 15 Dec 2024 First Prev 561–640 of 707 Next Last