OFFSET
0,5
COMMENTS
Inverse Lah transform of the Bell numbers (A000110).
LINKS
N. J. A. Sloane, Transforms
FORMULA
a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n-1,k-1)*Bell(k)*n!/k!, where Bell() = A000110.
MAPLE
a:= proc(n) option remember; add((-1)^(n-k)*n!/k!*
binomial(n-1, k-1)*combinat[bell](k), k=0..n)
end:
seq(a(n), n=0..30); # Alois P. Heinz, Jul 26 2018
MATHEMATICA
nmax = 24; CoefficientList[Series[Exp[Exp[x/(1 + x)] - 1], {x, 0, nmax}], x] Range[0, nmax]!
Table[Sum[(-1)^(n - k) Binomial[n - 1, k - 1] BellB[k] n!/k!, {k, 0, n}], {n, 0, 24}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Jul 26 2018
STATUS
approved