A155202 G.f.: A(x) = exp( Sum_{n>=1} (2^n - 1)^n * x^n/n ), a power series in x with integer coefficients.

1, 1, 5, 119, 12783, 5739069, 10426379903, 76135573607705, 2234839096465512877, 263966776643953756165279, 125532809982533901346598445525, 240383033223427436734891985275952307

Offset

0,3

Comments

More generally, for m integer, exp( Sum_{n>=1} (m^n + y)^n * x^n/n ) is a power series in x and y with integer coefficients.

Links

Table of n, a(n) for n=0..11.

Example

G.f.: A(x) = 1 + x + 5*x^2 + 119*x^3 + 12783*x^4 + 5739069*x^5 +...
log(A(x)) = x + 3^2*x^2/2 + 7^3*x^3/3 + 15^4*x^4/4 + 31^5*x^5/5 +...

Prog

(PARI) {a(n)=polcoeff(exp(sum(m=1, n+1, (2^m-1)^m*x^m/m)+x*O(x^n)), n)}

Crossrefs

Cf. A155200, A155202, A155810 (triangle), variants: A155205, A155209.

Sequence in context: A065818 A139189 A338755 * A168599 A193328 A002008

Adjacent sequences: A155199 A155200 A155201 * A155203 A155204 A155205

Keyword

nonn

Author

Paul D. Hanna, Feb 04 2009

Status

approved