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A157312 G.f.: A(x) = exp(Sum_{n>=1} A157311(n)*x^n/n) = Product_{n>=1} (1 + A157311(n-1)*x^n). 2
1, 1, 1, 2, 5, 18, 84, 481, 3249, 25359, 224000, 2208441, 24019991, 285633470, 3685413373, 51271476627, 764944009086, 12182390286127, 206262410584138, 3699483818281188, 70067511789111404, 1397379232420943285 (list; graph; refs; listen; history; text; internal format)
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: A118187 A307773 A038720 * A175847 A089412 A058798

Adjacent sequences:  A157309 A157310 A157311 * A157313 A157314 A157315

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Mar 10 2009

STATUS

approved

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Last modified May 21 02:48 EDT 2019. Contains 323434 sequences. (Running on oeis4.)