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 A110137 #3 Mar 30 2012 18:59:08
%S A110137 1,2,7,22,79,286,1071,4070,15721,61506,243703,977366,3968169,16313842,
%T A110137 67942539,286769518,1227194947,5326324598,23451408843,104753097326,
%U A110137 474663076539,2181355670806,10163422480887,47988508807190
%N A110137 Diagonal sums of A110135 when read as a number triangle.
%F A110137 a(n)=sum{j=0..floor((n-2k)/2), C(n-2k, j)C(2(n-2k-j), n-2k)k^j}
%K A110137 easy,nonn
%O A110137 0,2
%A A110137 _Paul Barry_, Jul 13 2005