A375608 Expansion of e.g.f. 1 / (exp(x^2) - x).

1, 1, 0, -6, -36, -120, 240, 8400, 82320, 362880, -3507840, -103783680, -1268688960, -4843238400, 175429013760, 5052189542400, 68016191443200, 55329155481600, -23284682272051200, -668640423164313600, -9013925405784499200, 57340797108269875200

Offset

0,4

Links

Table of n, a(n) for n=0..21.

Formula

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

Prog

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

Crossrefs

Cf. A089148, A375609.

Cf. A375394, A375604.

Sequence in context: A262467 A225262 A253652 * A083374 A264366 A061707

Adjacent sequences: A375605 A375606 A375607 * A375609 A375610 A375611

Keyword

sign

Author

Seiichi Manyama, Aug 21 2024

Status

approved