A368272 Expansion of e.g.f. exp(-x) / (1 + x*exp(x)).

1, -2, 3, -1, -11, 19, 151, -799, -2295, 37367, -16469, -2114531, 9695533, 132142451, -1556927553, -6822608311, 234527654161, -360436983569, -35798255259821, 294290464165685, 5217729367883061, -102317187098688661, -517822188623299097, 31412148276241662049

Offset: 0

Author

Seiichi Manyama, Dec 19 2023

Keywords

• sign
• easy

Crossrefs

Cf. A302397, A368271, A368273.

Programs

PARI

a(n) = n!*sum(k=0, n, (-1)^(n-k)*(n-k-1)^k/k!);

Formula

a(n) = n! * Sum_{k=0..n} (-1)^(n-k) * (n-k-1)^k / k!.