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 A272432 #4 May 01 2016 10:46:42
%S A272432 1,1,1,7,9,31,403,757,2873,12607,333051,761377,3699435,16383121,
%T A272432 108710085,4855474267,28123899993,241045678351,2865769028107,
%U A272432 22701288941281,238433702214659,4399193720759677,46157742163810905,514035796837721671,8889375296702138075
%N A272432 Number of ordered set partitions of {1,2,...,n} such that no part has the same size as any of its four immediate predecessors.
%H A272432 Alois P. Heinz, <a href="/A272432/b272432.txt">Table of n, a(n) for n = 0..80</a>
%Y A272432 Column k=4 of A261959.
%K A272432 nonn
%O A272432 0,4
%A A272432 _Alois P. Heinz_, Apr 29 2016