This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A309113 #23 Mar 11 2023 06:57:39 %S A309113 1, %T A309113 100669616553523347122516032313645505168688116411019768627200000000000 %N A309113 Number of possible permutations of a Megaminx of size 2n+1. %C A309113 a(3) has 264 digits and a(4) has 574 digits. %C A309113 The Megaminx is a dodecahedron-shaped puzzle similar to the Rubik's Cube. The rotational axes of the pieces are perpendicular to the faces. Here only a Megaminx of odd size is considered, see the picture below showing the relationship between the Megaminx of size 2n and 2n+1. %H A309113 Amiram Eldar, <a href="/A309113/b309113.txt">Table of n, a(n) for n = 0..4</a> %H A309113 Michael Gottlieb's blogger, <a href="https://michael-gottlieb.blogspot.com/2008/05/number-of-positions-of-generalized.html">Notes on Twisty Puzzles</a> %H A309113 Jianing Song, <a href="/A309113/a309113.png">Relationship between the Megaminx of size 2n and 2n+1</a> %H A309113 Wikipedia, <a href="https://en.wikipedia.org/wiki/Megaminx">Megaminx</a> %F A309113 a(0) = 1; a(n) = 30! * 20! * 60!^(n^2-1) * 5!^(-12*n^2+12*n) * 2^(28-n) * 3^19 for n > 0. %e A309113 See the Michael Gottlieb link above. %o A309113 (PARI) a(n) = if(n, 30! * 20! * 60!^(n^2-1) * 5!^(-12*n^2+12*n) * 2^(28-n) * 3^19, 1) %Y A309113 Number of possible permutations of: tetrahedron puzzle (without tips: A309109, with tips: A309110); cube puzzle (A075152); octahedron puzzle (without tips: A309111, with tips: A309112); dodecahedron (this sequence). %K A309113 nonn,bref %O A309113 0,2 %A A309113 _Jianing Song_, Jul 13 2019