0,3

G.f.: A(x) = Product_{n>0} 1/(1-x^n-x^(2*n))^a(n-1).

A(x)=exp(A(x)x + 3A(x^2)x^2/2 + 4A(x^3)x^3/3 + 7A(x^4)x^4/4 + 11A(x^5)x^5/5 + ...) = 1 + x + 3x^2 + 7x^3 + 19x^4 + 48x^5 + 134x^6 + 362x^7 + ...

Cf. A000081, A000204.

Sequence in context: A026581 A001372 A049117 this_sequence A007288 A061646 A017926

Adjacent sequences: A073060 A073061 A073062 this_sequence A073064 A073065 A073066

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Aug 17 2002