A258644 Fourth arithmetic derivative of n.

0, 0, 0, 0, 4, 0, 0, 0, 80, 0, 0, 0, 176, 0, 1, 32, 368, 0, 1, 0, 112, 0, 0, 0, 240, 0, 16, 27, 368, 0, 0, 0, 752, 5, 0, 80, 272, 0, 1, 176, 220, 0, 0, 0, 608, 80, 1, 0, 1552, 5, 32, 48, 272, 0, 540, 176, 560, 0, 0, 0, 560, 0, 6, 44, 7168, 7, 0, 0, 284, 12, 0

Offset: 0

Author

Alois P. Heinz, Jun 06 2015

Keywords

• nonn
• look

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000

Crossrefs

Column k=4 of A258651.

Cf. A003415.

Programs

Maple

d:= n-> n*add(i[2]/i[1], i=ifactors(n)[2]):
A:= proc(n, k) option remember; `if`(k=0, n, d(A(n, k-1))) end:
a:= n-> A(n, 4):
seq(a(n), n=0..70);

Formula

a(n) = A003415^4(n).