OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..402
FORMULA
E.g.f: exp(x)*(1-x)*x/(1-2*x)^2.
a(n) = Sum_{k=1..n} k * A326659(n,k).
a(n) ~ n! * exp(1/2) * n * 2^(n-2). - Vaclav Kotesovec, Sep 19 2019
MAPLE
a:= n-> n!*coeff(series(exp(x)*(1-x)*x/(1-2*x)^2, x, n+1), x, n):
seq(a(n), n=0..23);
# second Maple program:
a:= proc(n) option remember; `if`(n<3, n^3,
2*(n+2)*a(n-1)-(4*n-1)*a(n-2)+2*(n-2)*a(n-3))
end:
seq(a(n), n=0..23);
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Exp[x](1-x)(x/(1-2x)^2), {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 15 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 18 2019
STATUS
approved