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 A178011 #11 May 28 2016 10:24:15 %S A178011 1,1,1,2,6,24,120,720,2520,13440,90720,725760,6652800,68428800, %T A178011 444787200,4151347200,46702656000,597793996800,8468748288000, %U A178011 130660687872000,1241276534784000,16550353797120000,260668072304640000,4587758072561664000,87932029724098560000 %N A178011 Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap). %H A178011 Alois P. Heinz, <a href="/A178011/b178011.txt">Table of n, a(n) for n = 0..479</a> %H A178011 Wikipedia, <a href="https://en.wikipedia.org/wiki/D-ary_heap">D-ary heap</a> %Y A178011 Simple 2-way heap A056971. %Y A178011 Column k=6 of A273693. %K A178011 nonn %O A178011 0,4 %A A178011 _R. H. Hardin_, May 17 2010 %E A178011 a(0), a(21)-a(24) from _Alois P. Heinz_, May 27 2016