OFFSET
1,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = (sigma_13(n)+20*sigma_7(n)-21*sigma_5(n))/10080.
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 23 2016
STATUS
approved