OFFSET
1,3
FORMULA
a(n) = n * Sum_{i=1..floor((n-1)/2)} n * i * (n-i) (floor((n-i)/i) - floor((n-i-1)/i)).
a(n) = n * A303385(n).
MATHEMATICA
Table[Sum[n*i (n - i) (Floor[(n - i)/i] - Floor[(n - i - 1)/i]), {i, Floor[(n - 1)/2]}], {n, 50}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Apr 24 2018
STATUS
approved