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 A178010 #11 May 28 2016 10:24:04 %S A178010 1,1,1,2,6,24,120,360,1680,10080,72576,604800,3326400,26611200, %T A178010 259459200,2905943040,36324288000,290594304000,3293402112000, %U A178010 44460928512000,675806113382400,11263435223040000,118266069841920000,1734569024348160000,29921315670005760000 %N A178010 Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/5)] (5-way heap). %H A178010 Alois P. Heinz, <a href="/A178010/b178010.txt">Table of n, a(n) for n = 0..484</a> %H A178010 Wikipedia, <a href="https://en.wikipedia.org/wiki/D-ary_heap">D-ary heap</a> %Y A178010 Simple 2-way heap A056971. %Y A178010 Column k=5 of A273693. %K A178010 nonn %O A178010 0,4 %A A178010 _R. H. Hardin_, May 17 2010 %E A178010 a(0), a(21)-a(24) from _Alois P. Heinz_, May 27 2016