OFFSET
1,2
FORMULA
G.f.: (1/(1 - x)) * Sum_{k>=1} k * x^(k^2) / (1 - x^(k^2)). - Ilya Gutkovskiy, May 14 2021
MAPLE
b:= n-> mul((i[1]^(iquo(i[2], 2)+1)-1)/(i[1]-1), i=ifactors(n)[2]):
a:= proc(n) a(n):= a(n-1)+b(n) end: a(0):=0:
seq(a(n), n=1..66); # Alois P. Heinz, May 14 2021
MATHEMATICA
Table[Sum[k*Floor[n/k^2], {k, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, May 09 2021
STATUS
approved