The Calendar hole will go live in approximately 10 days. Why not try and solve it ahead of time?
PalindromemordnilaP 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 561st yokasuretsu 617 124 11ms 10 Jul 2025 561st hamilton-bonds 617 124 10ms 24 Jul 2025 561st robin-scragg 617 124 10ms 18 Oct 2025 564th Andrey-Plotnikov 615 115 9ms 30 Sep 2025 565th aliakseikalosha 614 144 373ms 5 Sep 2024 566th KatieLG 🇬🇧 612 69 38ms 1 Sep 2024 567th Natanaelel 🇸🇪 611 112 14ms 15 May 2025 568th Shanethegamer 🇺🇸 610 102 4,008ms 25 Oct 2024 568th dokutan 610 102 3,847ms 26 Oct 2024 570th BambooleanLogic 🇸🇪 610 116 9ms 19 Nov 2024 570th acollett89 610 116 9ms 4 Aug 2025 572nd msbranicky 608 86 231ms 16 Sep 2024 573rd nhausspiegel 607 126 10ms 13 Sep 2024 574th MeWhenI 🇻🇦 605 86 683ms 15 Sep 2025 575th matsagad 602 127 10ms 16 Jan 2025 576th Arkadios200 602 132 96ms 11 Oct 2025 577th dokutan 601 76 815ms 3 Sep 2024 578th dokutan 601 147 399ms 3 Nov 2024 579th mamamia5x 600 118 10ms 12 Sep 2024 580th Shanethegamer 🇺🇸 600 134 412ms 1 Sep 2024 581st Shanethegamer 🇺🇸 599 107 91ms 1 Sep 2024 582nd inventshah 599 150 2ms 1 Sep 2024 583rd xyangst 598 128 11ms 12 Oct 2024 583rd 123mjb 598 128 10ms 19 Nov 2025 585th emgordon154 595 104 133ms 14 Nov 2024 586th MeWhenI 🇻🇦 595 177 43ms 4 Sep 2024 586th Shanethegamer 🇺🇸 595 177 51ms 4 Sep 2024 588th mousetail 🇳🇱 594 105 6ms 3 Sep 2024 589th BREMAUCY 🇫🇷 594 316 12ms 7 Aug 2025 590th KatieLG 🇬🇧 593 77 790ms 1 Sep 2024 591st CaedenHarper 🇨🇦 593 149 392ms 16 Oct 2025 592nd h3ra993huskp 🇯🇵 592 163 687ms 20 days ago 593rd KatieLG 🇬🇧 589 135 94ms 21 Nov 2025 594th luuumine 🇫🇷 586 204 194ms 18 Nov 2025 595th cbrt-x 584 151 121ms 11 Sep 2024 596th DialFrost 🇸🇬 583 107 7ms 1 Sep 2024 597th dokutan 582 181 44ms 1 Sep 2024 598th Mabeloid 🇳🇴 581 109 701ms 17 Sep 2024 599th Upload-and-View 🇺🇦 580 119 2ms 23 Jul 2025 600th GeorgeStechman 🇬🇧 580 122 10ms 5 Nov 2024 600th gigaprofisi 🇺🇸 580 122 9ms 10 Aug 2025 602nd snoozingnewt 🇨🇦 580 226 251ms 1 Sep 2024 603rd JohandeRuiter 🇳🇱 576 156 2ms 2 Sep 2024 604th xyangst 575 123 9ms 15 Oct 2024 605th vhoulbreque 🇫🇷 573 146 201ms 11 Nov 2025 606th dokutan 570 74 41ms 20 Feb 2025 607th emgordon154 570 133 15ms 16 Dec 2024 608th TeodorDyakov 🇧🇬 565 159 2ms 6 Sep 2025 609th HumanoidCPU 563 110 143ms 22 Nov 2025 610th tomh1012 562 126 9ms 18 Sep 2025 611th smiksky 🇺🇸 562 136 11ms 16 Oct 2024 612th MostParsingVex 562 160 33ms 30 Sep 2024 613th dokutan 561 132 3ms 1 Sep 2024 614th emgordon154 559 138 11ms 1 Jan 2025 615th Stockoh 🇫🇷 558 137 11ms 17 Oct 2024 616th brimstonetrader 554 138 10ms 17 Oct 2024 617th RedzGoose 🇦🇺 553 145 116ms 9 Sep 2024 618th dokutan 548 113 149ms 22 Oct 2024 619th msbranicky 548 135 3ms 1 Sep 2024 620th KatieLG 🇬🇧 539 128 2ms 2 Oct 2025 621st mm1013g 539 142 10ms 2 Sep 2024 622nd dokutan 539 155 242ms 1 Sep 2024 623rd Shanethegamer 🇺🇸 535 91 25ms 1 Sep 2024 624th snoozingnewt 🇨🇦 534 79 40ms 12 Oct 2025 625th albanian-laundromat 533 352 11ms 18 Sep 2025 626th trijin 529 118 5ms 5 Oct 2024 627th Shanethegamer 🇺🇸 528 183 452ms 24 Sep 2025 628th pickerj 524 146 12ms 12 Sep 2024 629th tomh1012 523 169 395ms 17 Sep 2025 630th ravnskjaer 🇩🇰 519 186 344ms 5 days ago 631st error256 515 134 2ms 24 Sep 2024 632nd CaedenHarper 🇨🇦 514 188 438ms 3 Oct 2025 633rd Shanethegamer 🇺🇸 512 141 105ms 16 days ago 634th rboath 506 159 109ms 18 Dec 2024 635th madex 🇩🇪 502 84 45ms 1 Sep 2024 636th snoozingnewt 🇨🇦 502 141 8ms 12 Oct 2025 637th dbut2 🇦🇺 502 261 254ms 3 Sep 2024 638th LukeBridges 🇬🇧 498 142 9ms 3 Sep 2024 639th snoozingnewt 🇨🇦 497 160 101ms 1 Sep 2024 640th MeWhenI 🇻🇦 497 181 2ms 13 Jun 2025 First Prev 561–640 of 713 Next Last