A370700 Expansion of e.g.f. exp(-x^2)/(1-x).

1, 1, 0, 0, 12, 60, 240, 1680, 15120, 136080, 1330560, 14636160, 176299200, 2291889600, 32069157120, 481037356800, 7697116627200, 130850982662400, 2355300044697600, 44750700849254400, 895014687427660800, 18795308435980876800, 413496757432991232000

Offset

0,5

Links

Table of n, a(n) for n=0..22.

Formula

a(n) = n! * Sum_{k=0..floor(n/2)} (-1)^k/k!.

Prog

(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-x^2)/(1-x)))
(PARI) a(n) = n!*sum(k=0, n\2, (-1)^k/k!);

Crossrefs

Cf. A000166, A370701.

Cf. A355268.

Sequence in context: A260356 A120571 A086950 * A374648 A074433 A280175

Adjacent sequences: A370697 A370698 A370699 * A370701 A370702 A370703

Keyword

nonn,easy

Author

Seiichi Manyama, Feb 27 2024

Status

approved