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 A226287 #13 Jul 12 2024 16:39:18 %S A226287 0,0,0,0,0,0,0,0,0,0,0,518400,25401600,1244678400,39829708800, %T A226287 1274550681600,34412868403200,929147446886400,23228686172160000, %U A226287 580717154304000000,14053355134156800000,340091194246594560000 %N A226287 a(n) = [n/2]!*[(n+1)/2]!*C([n/2],6)*C([(n+1)/2],6). %C A226287 Number of permutations of n elements with 12 odd displacements. %C A226287 Column 7 of A226288. %C A226287 Column k=12 of A145893, a diagonal of A145894. - _Alois P. Heinz_, May 29 2014 %H A226287 R. H. Hardin, <a href="/A226287/b226287.txt">Table of n, a(n) for n = 1..210</a> %K A226287 nonn %O A226287 1,12 %A A226287 _R. H. Hardin_, connection of formula with combinatoric problem via _N. J. A. Sloane_ in the Sequence Fans Mailing List, Jun 02 2013