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 A178956 #10 Apr 30 2013 07:51:18
%S A178956 1,-1,0,1,1,-1,-7,-13,169,233,17,-18847,-43957,26023,429007,31505483,
%T A178956 -31381783,-753299101,-7372705283,195152846389,632396244331,
%U A178956 -52258919107,-447065769153911,-13584264183406001,34831349327448893,674219621951483119,2113978805943481381,-6602691591860999071,-370308752490094361609,-95867348590727618473,752151788353653780085507
%N A178956 Numerators in expansion of 1/(Sum_{n >= 0} (x^n/n!)*binomial(2n,n)/(n+1)).
%C A178956 This is the reciprocal of the e.g.f. for the Catalan numbers.
%e A178956 1, -1, 0, 1/6, 1/12, -1/60, -7/180, -13/1008, 169/20160, 233/25920, 17/14175, -18847/6652800, -43957/23950080, 26023/141523200, 429007/544864320, 31505483/100590336000, ...
%Y A178956 Cf. A000108, A178957 (denominators), A178955, A144186/A144187.
%K A178956 sign,frac
%O A178956 0,7
%A A178956 _N. J. A. Sloane_, Dec 31 2010