A205775 G.f. satisfies: A(x) = 1/Product_{n>=1} (1 - x^n*A(x^n)^n).

1, 1, 3, 8, 26, 79, 276, 936, 3376, 12259, 45648, 171739, 655664, 2524835, 9813259, 38410167, 151332137, 599541153, 2387199083, 9547195445, 38335338712, 154484001619, 624579964260, 2532713370789, 10298393401623, 41979975505800, 171522040764060

Offset

0,3

Links

Table of n, a(n) for n=0..26.

Example

 G.f.: A(x) = 1 + x + 3*x^2 + 8*x^3 + 26*x^4 + 79*x^5 + 276*x^6 + 936*x^7 +...
where
A(x) = 1/((1 - x*A(x)) * (1 - x^2*A(x^2)^2) * (1 - x^3*A(x^3)^3) *...).

Prog

 (PARI) {a(n)=local(A=1+x); for(i=1, n, A=1/prod(k=1, n, (1-x^k*subst(A, x, x^k+x*O(x^n))^k))); polcoeff(A, n)}

Crossrefs

Cf. A050383, A196192, A205774, A196191.

Sequence in context: A306485 A148801 A131910 * A331320 A148802 A255712

Adjacent sequences: A205772 A205773 A205774 * A205776 A205777 A205778

Keyword

nonn

Author

Paul D. Hanna, Jan 31 2012

Status

approved