A369865 - OEIS

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A369865

a(n) = n * Sum_{p|n, p prime} mu(n/p)^2 / p.

0, 1, 1, 2, 1, 5, 1, 0, 3, 7, 1, 6, 1, 9, 8, 0, 1, 6, 1, 10, 10, 13, 1, 0, 5, 15, 0, 14, 1, 31, 1, 0, 14, 19, 12, 0, 1, 21, 16, 0, 1, 41, 1, 22, 15, 25, 1, 0, 7, 10, 20, 26, 1, 0, 16, 0, 22, 31, 1, 30, 1, 33, 21, 0, 18, 61, 1, 34, 26, 59, 1, 0, 1, 39, 15, 38, 18, 71, 1

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OFFSET

1,4

LINKS

Table of n, a(n) for n=1..79.

FORMULA

a(p^k) = p^(k-1) for p prime and 1 <= k <= 2, else 0 if k >= 3. - Wesley Ivan Hurt, Jun 26 2024

MATHEMATICA

Table[n*DivisorSum[n, (MoebiusMu[n/#]^2)/# &, PrimeQ[#] &], {n, 100}]

CROSSREFS

Cf. A008683, A143519, A369742, A369864.

Sequence in context: A317301 A131915 A078036 * A175178 A348494 A256541

Adjacent sequences: A369862 A369863 A369864 * A369866 A369867 A369868

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, Feb 03 2024

STATUS

approved