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 A015040 #4 Mar 30 2012 17:20:37
%S A015040 1,1,82,538813,286395753646,12328630051958712010,
%T A015040 42987364825231475446819490020,
%U A015040 12140904342526064511968354988982391829685
%N A015040 q-Catalan numbers (binomial version) for q=9.
%F A015040 {1 / (n+1)_q} {2 n choose n}_q.
%K A015040 nonn,easy
%O A015040 0,3
%A A015040 _Olivier Gérard_