A161637 G.f.: A(x) = exp( Sum_{n>=1} x^n/(1 - 2^(n^2)*x^n)/n ).

1, 1, 3, 7, 25, 49, 421, 589, 20051, 109571, 6897743, 7158695, 12593657691, 12622726251, 80459328159219, 305712703088131, 2306380162670320841, 2307152558777717417, 269444164561317686825525, 269453394201317013516237

Offset: 0

Author

Paul D. Hanna, Jun 18 2009

Keywords

• nonn

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 7*x^3 + 25*x^4 + 49*x^5 +...
log(A(x)) = x/(1-2*x) + x^2/(1-2^4*x^2)/2 + x^3/(1-2^9*x^3)/3 +...
		

Crossrefs

Cf. A158097.

Programs

PARI

{a(n)=if(n==0, 1, polcoeff(exp(sum(k=1, n, x^k/(1-2^(k^2)*x^k +x*O(x^n))/k)), n))}