OFFSET
1,2
EXAMPLE
a(10) = Sum_{d|10} d * floor(sqrt(d)) = 1*1 + 2*1 + 5*2 + 10*3 = 43.
MATHEMATICA
Table[Sum[k*Floor[Sqrt[k]] (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 80}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, May 19 2021
STATUS
approved