A157312 G.f.: A(x) = exp(Sum_{n>=1} A157311(n)*x^n/n) = Product_{n>=1} (1 + A157311(n-1)*x^n).

1, 1, 1, 2, 5, 18, 84, 481, 3249, 25359, 224000, 2208441, 24019991, 285633470, 3685413373, 51271476627, 764944009086, 12182390286127, 206262410584138, 3699483818281188, 70067511789111404, 1397379232420943285

Offset

0,4

Links

Table of n, a(n) for n=0..21.

Example

G.f.: A(x) = 1 + x + x^2 + 2*x^3 + 5*x^4 + 18*x^5 + 84*x^6 +...
where both the exponential:
A(x) = exp(x + x^2/2 + 4*x^3/3 + 13*x^4/4 + 66*x^5/5 + 394*x^6/6 +...)
and the product:
A(x) = (1 + x)(1 + x^2)(1 + x^3)(1 + 4*x^4)(1 + 13*x^5)(1 + 66*x^6)*...
generate A(x) using the same coefficients (after initial term):
A157311=[1,1,1,4,13,66,394,2759,22005,198049,1979646,21776107,...].

Crossrefs

Cf. A157311.

Sequence in context: A307773 A332776 A038720 * A175847 A089412 A058798

Adjacent sequences: A157309 A157310 A157311 * A157313 A157314 A157315

Keyword

nonn

Author

Paul D. Hanna, Mar 10 2009

Status

approved