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 A113140 #3 Mar 30 2012 18:59:12
%S A113140 1,3,14,68,347,1819,9712,52532,286905,1578679,8738278,48601968,
%T A113140 271406347,1520725095,8545396208,48138689272,271768537793,
%U A113140 1537212749339,8709732836238,49423440297324,280835252080651,1597731101233763
%N A113140 Diagonal sums of a Delannoy related triangle.
%C A113140 Diagonal sums of A113139.
%F A113140 a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, C(n-2k, j)C(n-k+j, k+j)}}.
%K A113140 easy,nonn
%O A113140 0,2
%A A113140 _Paul Barry_, Oct 15 2005