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 A118341 #3 Mar 30 2012 18:36:56
%S A118341 1,2,9,48,282,1762,11488,77270,532239,3735488,26617976,192061278,
%T A118341 1400453568,10303466638,76391703591,570195719792,4281169118106,
%U A118341 32312317899352,245016567557504,1865677590201192,14259825593908356
%N A118341 Self-convolution square of A108447.
%o A118341 (PARI) {a(n)=polcoeff((serreverse(x*(1-x+sqrt((1-x)*(1-5*x)+x*O(x^n)))/2/(1-x))/x)^2,n)}
%Y A118341 Cf. A108447, A118342, A118343.
%K A118341 nonn
%O A118341 0,2
%A A118341 _Paul D. Hanna_, Apr 25 2006