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 A098510 #4 Mar 30 2012 18:58:59
%S A098510 1,2,5,20,49,210,429,2860,7293,34034,113373,537472,1359507,6611810,
%T A098510 24627135,37917616,177181213,973514514,1647439975,12026570280,
%U A098510 17818756259,98555142278,502860886675,4577646742140,6402665244089
%N A098510 Row sums of a matrix associated to the inverse of a Catalan scaled binomial matrix.
%C A098510 Row sums of A098509.
%F A098510 a(n)=sum{k=0..n, denominator((n+1)binomial(n, k)/binomial(2n, n))}
%K A098510 easy,nonn
%O A098510 0,2
%A A098510 _Paul Barry_, Sep 11 2004