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A066859
Product of sums of divisors and non-divisors.
1
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
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
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 23 2002
STATUS
approved