OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..366
Wikipedia, Permutation
FORMULA
MAPLE
a:= proc(s) option remember; `if`(n<3, (3*n-1)*n/2,
(8*n-12)*a(n-1)-(16*n^2-64*n+59)*a(n-2)-(4*n-10)*a(n-3))
end:
seq(a(n), n=0..20);
MATHEMATICA
A[n_, k_] := -Sum[(-1)^j*Binomial[n, j]*(n+k-j)!, {j, 1, n}]/k!;
a[n_] := A[n, n];
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 23 2019
STATUS
approved