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 A107028 #3 Mar 30 2012 18:59:07
%S A107028 1,3,5,9,19,49,155,591,2651,13689,80009,522193,3762273,29629483,
%T A107028 252966249,2325176147,22874076091,239615657133,2661015200515,
%U A107028 31207545002577,385191232715737,4988767088734625,67615869255979521
%N A107028 Row sums of number triangle A107027.
%F A107028 a(n)=sum{k=0..n, (n-k-1)C((n-k)*k, k)-(n-k-2)*sum{j=0..k, C((n-k)*k, j)}}
%K A107028 easy,nonn
%O A107028 0,2
%A A107028 _Paul Barry_, May 09 2005