OFFSET
0,4
COMMENTS
Lah transform of A000166.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..400
N. J. A. Sloane, Transforms
FORMULA
a(n) = Sum_{k=0..n} binomial(n-1,k-1)*A000166(k)*n!/k!.
a(n) ~ sqrt(Pi) * 2^(n - 1/2) * n^(n + 1/2) / exp(n+1). - Vaclav Kotesovec, Mar 26 2019
a(n) = n!*(LaguarreL(n,1) + Sum_{j=0..n-2} 2^(n-j-2)*LaguerreL(j,1)). - G. C. Greubel, Mar 09 2021
MAPLE
a:=series(exp(x/(x - 1))*(1 - x)/(1 - 2*x), x=0, 22): seq(n!*coeff(a, x, n), n=0..21); # Paolo P. Lava, Mar 26 2019
MATHEMATICA
nmax = 21; CoefficientList[Series[Exp[x/(x - 1)] (1 - x)/(1 - 2 x), {x, 0, nmax}], x] Range[0, nmax]!
Table[Sum[Binomial[n - 1, k - 1] Subfactorial[k] n!/k!, {k, 0, n}], {n, 0, 21}]
A317096[n_]:= A317096[n]= n!*(LaguerreL[n, 1] + Sum[2^(n-j-2)*LaguerreL[j, 1], {j, 0, n-2}]); Table[A317096[n], {n, 0, 25}] (* G. C. Greubel, Mar 09 2021 *)
PROG
(Sage)
def A317096(n): return factorial(n)*( gen_laguerre(n, 0, 1) + sum(2^(n-j-2)*gen_laguerre(j, 0, 1) for j in (0..n-2)) )
[A317096(n) for n in (0..25)] # G. C. Greubel, Mar 09 2021
(Magma)
R<x>:=PowerSeriesRing(Rationals(), 26);
Coefficients(R!(Laplace( ((1-x)/(1-2*x))*Exp(x/(x-1)) ))); // G. C. Greubel, Mar 09 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 01 2018
STATUS
approved