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 A099236 #3 Mar 30 2012 18:59:00
%S A099236 1,2,3,5,9,18,39,91,226,594,1643,4763,14419,45444,148714,504150,
%T A099236 1766930,6390720,23815168,91306968,359694457,1454213026,6027213531,
%U A099236 25583995337,111118605583,493407322280,2238131105770,10363617299670,48954143141361
%N A099236 Sums of antidiagonals of A099233.
%F A099236 a(n)=sum{j=0..n, sum{k=0..n-j, binomial(j(n-j-k), k)}}
%K A099236 easy,nonn
%O A099236 0,2
%A A099236 _Paul Barry_, Oct 08 2004