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%I #12 Aug 06 2012 23:30:19
%S 1,1,2,8,54,544,7508,133704,2943194,77589536,2391477804,84582890704,
%T 3382005372970,151034046369696,7458091839548356,403808650013237224,
%U 23801728042233670770,1517930142778063770304,104179592763803229618620
%N G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n^2).
%F a(n) = 1 - Sum_{j=0..n-1} a(j) * (-1)^(n-j) * C(j^2 + n-j-1, n-j) for n>0, with a(0)=1.
%e 1/(1-x) = 1 + x/(1+x) + 2*x^2/(1+x)^4 + 8*x^3/(1+x)^9 + 54*x^4/(1+x)^16 +...
%o (PARI) {a(n)=if(n==0,1,polcoeff(-(1-x)*sum(m=0,n-1,a(m)*x^m/(1+x +x*O(x^n))^(m^2)),n))}
%o (PARI) {a(n)=if(n==0, 1, 1 - sum(j=0, n-1, a(j)*(-1)^(n-j)*binomial(j^2+n-j-1, n-j)))}
%Y Cf. A141761, A177447, A215241, A215242, A215243.
%K nonn
%O 0,3
%A _Paul D. Hanna_, Dec 24 2010
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