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A171777 E.g.f.: A(x) = exp( Sum_{n>=1} 2^(n(n-1)/2) * x^n/n ). 0
1, 1, 3, 23, 473, 27057, 4102027, 1539365191, 1365364095921, 2783117747148641, 12795599930746180499, 130882205973999096722679, 2946911413331842739385098377, 144807670567304192694224250060817 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..13.

EXAMPLE

E.g.f.: A(x) = 1 + x + 3*x^2/2! + 23*x^3/3! + 473*x^4/4! +...

log(A(x)) = x + 2*x^2/2 + 2^3*x^3/3 + 2^6*x^4/4 + 2^10*x^5/5 +...

PROG

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

CROSSREFS

Cf. A171776, A155200.

Sequence in context: A116986 A271962 A268668 * A154896 A134050 A101191

Adjacent sequences:  A171774 A171775 A171776 * A171778 A171779 A171780

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jan 23 2010

STATUS

approved

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Last modified January 29 07:03 EST 2020. Contains 331337 sequences. (Running on oeis4.)