OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
MAPLE
b:= proc(n, k) option remember;
`if`(k=0, n!, b(n, k-1)-b(n-1, k-1))
end:
a:= n-> add(b(n-k, k)*(-1)^k, k=0..n/2):
seq(a(n), n=0..23);
MATHEMATICA
b[n_, k_] := b[n, k] = If[k == 0, n!, b[n, k-1] - b[n-1, k-1]];
a[n_] := Sum[b[n-k, k]*(-1)^k, {k, 0, n/2}];
Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jun 05 2022, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 03 2021
STATUS
approved