A209935 G.f.: 1 = Sum_{n>=0} a(n)*x^n*Product_{k=1..n+1} (1-k^2*x) for n>0 with a(0)=1.

1, 1, 5, 66, 1735, 77587, 5339632, 527780778, 71236904519, 12635518401687, 2857729962091681, 804340796768258860, 276170316701087964628, 113757566198465278521124, 55424247710747076665462268, 31554099393732823158673973698

Offset: 0

Author

Paul D. Hanna, Mar 15 2012

Keywords

• nonn

Examples

			G.f.: 1 = 1*(1-x) + 1*x*(1-x)*(1-2^2*x) + 5*x^2*(1-x)*(1-2^2*x)*(1-3^2*x) + 66*x^3*(1-x)*(1-2^2*x)*(1-3^2*x)*(1-4^2*x) + 1735*x^4*(1-x)*(1-2^2*x)*(1-3^2*x)*(1-4^2*x)*(1-5^2*x) +...
		

Crossrefs

Cf. A082161.

Programs

PARI

{a(n)=if(n==0, 1, polcoeff(1-sum(k=0, n-1, a(k)*x^k*prod(j=1, k+1, 1-j^2*x+x*O(x^n))), n))}
for(n=0,20,print1(a(n),", "))