OFFSET
1,4
COMMENTS
EXAMPLE
The prime factorization of 24 is 2^3 * 3, so a(24) = 24^2 * (1/2^2 + 1/2^(2*2) + 1/2^(2*3) + 1/3^2) = 253.
PROG
(PARI) a(n) = my(f=factor(n)); sum(k=1, #f~, sum(j=1, f[k, 2], n^2 / f[k, 1]^(2*j)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel Suteu, Dec 22 2018
STATUS
approved