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 A015038 #4 Mar 30 2012 17:20:37
%S A015038 1,1,50,120443,14176726502,81731562414097002,
%T A015038 23087367704084630526165300,319559330566264937870155968502833579,
%U A015038 216732554100846341408822827225378918525605881606
%N A015038 q-Catalan numbers (binomial version) for q=7.
%F A015038 {1 / (n+1)_q} {2 n choose n}_q.
%K A015038 nonn,easy
%O A015038 0,3
%A A015038 _Olivier Gérard_