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 A015055 #4 Mar 30 2012 17:20:37
%S A015055 1,1,145,3008593,8984079652177,3863006623296221245777,
%T A015055 239187274872617784539568647160145,
%U A015055 2132617833186094044575170253829071294297506129
%N A015055 q-Catalan numbers (binomial version) for q=12.
%F A015055 {1 / (n+1)_q} {2 n choose n}_q.
%K A015055 nonn,easy
%O A015055 0,3
%A A015055 _Olivier Gérard_