A066859 Product of sums of divisors and non-divisors.

0, 0, 8, 21, 54, 108, 160, 315, 416, 666, 648, 1400, 1078, 1944, 2304, 3255, 2430, 5148, 3400, 7056, 6368, 7812, 6048, 14400, 9114, 12978, 13520, 19600, 12150, 28296, 14848, 29295, 24624, 29214, 27936, 52325, 25270, 40860, 40544, 65700, 34398, 77472, 39688

Offset

1,3

Comments

A000203(n) + A024816(n) = A000217(n).

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000203(n)*A024816(n).

Maple

a:= n-> (s-> s*(n*(n+1)/2-s))(numtheory[sigma](n)):
seq(a(n), n=1..45);  # Alois P. Heinz, Feb 05 2021

Prog

(PARI) a(n) = my(s=sigma(n)); s*(n*(n+1)/2 - s); \\ Michel Marcus, Feb 05 2021

Crossrefs

Cf. A000203, A024816, A000217.

Sequence in context: A344599 A138179 A067334 * A227653 A296198 A301538

Adjacent sequences: A066856 A066857 A066858 * A066860 A066861 A066862

Keyword

nonn

Author

Reinhard Zumkeller, Jan 23 2002

Status

approved