OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
FORMULA
a(n) = Sum_{k=0..n} (-1)^k * A047920(n,k).
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)*(-1)^k, k=0..n):
seq(a(n), n=0..23);
MATHEMATICA
a[n_] := Sum[(-1)^(j+k)*Binomial[k, j]*(n-j)!, {j, 0, n}, {k, 0, n}];
Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jun 04 2022 *)
PROG
(PARI) row(n) = vector(n+1, k, k--; sum(j=0, n, (-1)^j * binomial(k, j)*(n-j)!)); \\ A047920
a(n) = my(v=row(n)); sum(k=1, n+1, (-1)^k*row[k]); \\ Michel Marcus, Sep 04 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 01 2021
STATUS
approved