OFFSET
1,2
COMMENTS
If p is prime, a(p) = Sum_{d|p} d * floor(p/d^2) = 1*p + p*0 = p.
EXAMPLE
a(6) = 8; Sum_{d|6} d * floor(6/d^2) = 1*6 + 2*1 + 3*0 + 6*0 = 8.
MATHEMATICA
Table[Sum[(1 - Ceiling[n/k] + Floor[n/k]) k*Floor[n/k^2], {k, n}], {n, 100}]
PROG
(PARI) a(n) = sumdiv(n, d, d*(n\d^2)); \\ Michel Marcus, May 17 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, May 16 2021
STATUS
approved