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A113060
a(n) = n!*Sum_{k=0..n} bell(k+1)/k!, n=0,1..., where bell(n) are the Bell numbers, cf. A000110.
1
1, 3, 11, 48, 244, 1423, 9415, 70045, 581507, 5349538, 54173950, 600127047, 7229169001, 94170096335, 1319764307235, 19806944750672, 316993980880556, 5389579751775611, 97018268274166055
OFFSET
0,2
LINKS
FORMULA
a(n) = (-1)^n*n!*Sum_{p >=1} LaguerreL(n, -n-1, p)/(p-1)!/exp(1), n>=0.
E.g.f.: exp(exp(x)-1+x)/(1-x).
Representation as the n-th moment of a positive weight function on a positive half-axis: The weight function is a piecewise continuous function which is a weighted infinite sum of shifted exponential distributions, in Maple notation: a(n)=int(x^n*sum(exp(p-x)*Heaviside(x-p)/(p-1)!, p=1..infinity))/(exp(1)), n=0, 1...
a(n) ~ exp(exp(1)) * n!. - Vaclav Kotesovec, Jun 26 2022
MATHEMATICA
With[{nmax = 50}, CoefficientList[Series[Exp[Exp[x] - 1 + x]/(1 - x), {x, 0, nmax}], x]*Range[0, nmax]!] (* G. C. Greubel, May 23 2018 *)
Table[n!Sum[BellB[k+1]/k!, {k, 0, n}], {n, 0, 20}] (* Harvey P. Dale, May 03 2020 *)
PROG
(PARI) x='x+O('x^30); Vec(serlaplace(exp(exp(x)-1+x)/(1-x) )) \\ G. C. Greubel, May 23 2018
(Magma) m:=25; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Exp(Exp(x)-1+x)/(1-x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, May 23 2018
CROSSREFS
Cf. A113059.
Sequence in context: A367874 A317170 A127087 * A372623 A186374 A187249
KEYWORD
nonn
AUTHOR
Karol A. Penson, Oct 13 2005
STATUS
approved