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 A176720 #2 Mar 30 2012 18:37:21
%S A176720 1,2,4,8,18,44,112,288,744,1938,5104,13584,36456,98468,267376,729488,
%T A176720 1999074,5500412,15189636,42084952,116949848,325878288,910333152,
%U A176720 2548892864,7152113760,20108587038,56641227416,159820928328
%N A176720 G.f. satisfies: A(x) = 1 + Sum_{n>=0} 2*x^(n^2)*A(x)^n.
%e A176720 G.f.: A(x) = 1 + 2*x + 4*x^2 + 8*x^3 + 18*x^4 + 44*x^5 + 112*x^6 +...
%e A176720 A(x) = 1 + 2*x*A(x) + 2*x^4*A(x)^2 + 2*x^9*A(x)^3 + 2*x^16*A(x)^4 + ...
%o A176720 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=1+sum(m=1,n,2*(A+x*O(x^n))^m*x^(m^2)));polcoeff(A,n)}
%Y A176720 Cf. A157134, A176719.
%K A176720 nonn
%O A176720 0,2
%A A176720 _Paul D. Hanna_, Apr 25 2010
%E A176720 Edited by _Paul D. Hanna_, Apr 27 2010