A358611 - OEIS

%I #13 Nov 25 2022 06:34:18

%S 1,1,2,6,24,119,719,5038,40314,362856,3628681,39916081,478996562,

%T 6226980486,87177928344,1307670739319,20922749971919,355686949099438,

%U 6402367478747514,121645013230903656,2432900700505900681,51090921248959468081,1124000372090658580562

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

%H Seiichi Manyama, <a href="/A358611/b358611.txt">Table of n, a(n) for n = 0..449</a>

%F a(n) = n * a(n-1) - a(n-5) + n * a(n-6) for n > 5.

%o (PARI) a(n) = sum(k=0, n\5, (-1)^k*(n-5*k)!);

%Y Cf. A358607, A358608, A358609.

%Y Cf. A358500.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Nov 23 2022