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 A098506 #7 Nov 18 2012 12:15:36
%S A098506 1,2,3,8,9,22,19,100,101,266,435,860,1603,4110,6529,4672,12397,21558,
%T A098506 7845,57648,9447,50190,199053,1880620,1710309,7344462,7529113,
%U A098506 34610408,555889,3316906,21528385,167087336,124402817,73289470,764401867
%N A098506 Row sums of the number triangle A098505.
%H A098506 Harvey P. Dale, <a href="/A098506/b098506.txt">Table of n, a(n) for n = 0..1000</a>
%F A098506 a(n)=sum{k=0..n, numerator((n+1)binomial(n, k)/binomial(2n, n))}
%t A098506 Table[Sum[Numerator[((n+1)Binomial[n,k])/Binomial[2n,n]],{k,0,n}],{n,0,40}] (* _Harvey P. Dale_, Nov 18 2012 *)
%K A098506 easy,nonn
%O A098506 0,2
%A A098506 _Paul Barry_, Sep 11 2004