OFFSET
1,2
COMMENTS
If p is prime, a(p) = Sum_{d|p} d^abs(mu(d)) = 1^1 + p^1 = p + 1.
EXAMPLE
a(10) = Sum_{d|10} d^abs(mu(d)) = 1^1 + 2^1 + 5^1 + 10^1 = 18.
MATHEMATICA
Table[Sum[k^Abs[MoebiusMu[k]] (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, May 20 2021
STATUS
approved