A358606 a(n) = Sum_{k=0..floor(n/5)} (-1)^k * (n-4*k)!/(n-5*k)!.

1, 1, 1, 1, 1, 0, -1, -2, -3, -4, -3, 0, 5, 12, 21, 26, 21, 0, -43, -114, -195, -244, -195, 42, 581, 1440, 2421, 2990, 2157, -1644, -9955, -22974, -37515, -44248, -24219, 50310, 205661, 442140, 689997, 740906, 190245, -1534224, -4941355, -9887058, -14429619, -13255900, 3510141

Offset: 0

Author

Seiichi Manyama, Nov 23 2022

Keywords

• sign

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A358603, A358604, A358605.

Cf. A357570.

Programs

PARI

a(n) = sum(k=0, n\5, (-1)^k*(n-4*k)!/(n-5*k)!);

Formula

a(n) = (4 * a(n-1) - n * a(n-5) + 1)/5 for n > 4.