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 A024498 #5 Nov 28 2014 14:12:01
%S A024498 2,3,6,17,50,154,490,1608,5402,18475,64130,225346,800046,2865471,
%T A024498 10341168,37567524,137270954,504174183,1860277042,6892326441,
%U A024498 25631327354,95640861987,357975249026,1343650153462,5056424257510,19073789728773,72108867616596
%N A024498 a(n) = [ C(2n,n)/n ].
%t A024498 Table[Floor[Binomial[2n,n]/n],{n,40}] (* _Harvey P. Dale_, Nov 28 2014 *)
%K A024498 nonn
%O A024498 1,1
%A A024498 _Clark Kimberling_