A372715 - OEIS

A372715

a(n) = tau(3*n-2) = A000005(3*n-2).

1, 3, 2, 4, 2, 5, 2, 4, 3, 6, 2, 4, 2, 8, 2, 4, 3, 6, 4, 4, 2, 7, 2, 8, 2, 6, 2, 4, 4, 8, 4, 4, 2, 9, 2, 4, 2, 10, 4, 4, 3, 6, 2, 8, 4, 8, 2, 4, 4, 6, 2, 8, 2, 12, 2, 4, 3, 6, 6, 4, 2, 8, 4, 8, 2, 9, 2, 4, 4, 10, 2, 4, 4, 12, 2, 4, 2, 8, 4, 8, 2, 6, 4, 8, 4, 9

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..86.

FORMULA

Sum_{k=1..n} a(k) ~ 2*n * (log(n) + 2*gamma - 1 + 2*log(3)) / 3, where gamma is the Euler-Mascheroni constant A001620.

MATHEMATICA

Table[DivisorSigma[0, 3*n-2], {n, 1, 150}]

CROSSREFS

Cf. A372713, A372714.

Cf. A000005, A099777, A099774.