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 A273696 #6 May 28 2016 10:26:08 %S A273696 1,1,1,2,6,24,120,720,5040,40320,362880,1814400,13305600,119750400, %T A273696 1245404160,14529715200,186810624000,2615348736000,39520825344000, %U A273696 640237370572800,6082255020441600,81096733605888000,1277273554292736000,22480014555552153600 %N A273696 Number of 9-ary heaps on n elements. %H A273696 Alois P. Heinz, <a href="/A273696/b273696.txt">Table of n, a(n) for n = 0..472</a> %H A273696 Wikipedia, <a href="https://en.wikipedia.org/wiki/D-ary_heap">D-ary heap</a> %Y A273696 Column k=9 of A273693. %K A273696 nonn %O A273696 0,4 %A A273696 _Alois P. Heinz_, May 28 2016