OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..357
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 858
Vladimir Kruchinin, The method for obtaining expressions for coefficients of reverse generating functions, arXiv:1211.3244 [math.CO], 2012.
I. Mezo, A. Baricz, On the generalization of the Lambert W function with applications in theoretical physics, arXiv preprint arXiv:1408.3999 [math.CA], 2014-2015.
FORMULA
E.g.f.: RootOf(exp(_Z)*x*_Z+exp(_Z)*x-_Z).
E.g.f. A(x) = sum(n>0, a(n)*x^n/n!) is inverse to F(x)=x*exp(-x)/(1+x), a(n)=(n-1)!*sum_{i=0..n-1} (n^(n-i-1)*binomial(n,i))/(n-i-1)!, n>0. - Vladimir Kruchinin, Jan 31 2012
a(n) ~ 5^(-1/4) * ((3+sqrt(5))/2)^n * exp((sqrt(5)-3)*n/2) * n^(n-1). - Vaclav Kotesovec, Jan 23 2014
MAPLE
spec := [S, {B=Prod(Z, C), C=Set(S), S=Sequence(B, 1<= card)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
MATHEMATICA
CoefficientList[InverseSeries[Series[x/(E^x*(1+x)), {x, 0, 20}], x], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2014 *)
PROG
(Maxima) a(n):=((n-1)!*sum((n^(n-i-1)*binomial(n, i))/(n-i-1)!, i, 0, n-1)); /* Vladimir Kruchinin, Jan 31 2012 */
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
STATUS
approved