A386573 Sum of the squarefree balanced divisors of n.
1, 3, 4, 3, 1, 12, 1, 3, 4, 3, 1, 12, 1, 17, 19, 3, 1, 12, 1, 3, 4, 3, 1, 12, 1, 3, 4, 17, 1, 57, 1, 3, 4, 3, 36, 12, 1, 3, 4, 3, 1, 68, 1, 3, 19, 3, 1, 12, 1, 3, 4, 3, 1, 12, 1, 17, 4, 3, 1, 57, 1, 3, 4, 3, 1, 12, 1, 3, 4, 122, 1, 12, 1, 3, 19, 3, 1, 90, 1, 3, 4, 3, 1, 68, 1, 3, 4, 3, 1, 57, 1, 3, 4, 3, 1, 12, 1, 17, 4, 3
Offset: 1
Keywords
Programs
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Mathematica
Table[Sum[d (1 - Ceiling[DivisorSigma[1, d]/EulerPhi[d]] + Floor[DivisorSigma[1, d]/EulerPhi[d]]) MoebiusMu[d]^2, {d, Divisors[n]}], {n, 100}]
Formula
a(n) = Sum_{d|n} d * c(d) * mu(d)^2, where c = A351114.
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