OFFSET
0,8
COMMENTS
This sequence mimics the Maclaurin series for the function x -> exp(-x).
The series in the name is well defined; for any n > 0, only the first A065027(n) terms are different from zero.
EXAMPLE
For n = 3:
- we have:
k floor(3^k / k!)
- ---------------
0 1
1 3
2 4
3 4
4 3
5 2
6 1
>=7 0
- hence a(3) = 1 - 3 + 4 - 4 + 3 - 2 + 1 = 0.
PROG
(PARI) a(n) = { my (v=0, d=1, s=+1); for (k=1, oo, if (d<1, return (v), v += s*floor(d); d *= n/k; s = -s)) }
CROSSREFS
KEYWORD
sign
AUTHOR
Rémy Sigrist, Jul 12 2019
STATUS
approved