A372784 a(n) = tau(4*n) = A000005(4*n).

3, 4, 6, 5, 6, 8, 6, 6, 9, 8, 6, 10, 6, 8, 12, 7, 6, 12, 6, 10, 12, 8, 6, 12, 9, 8, 12, 10, 6, 16, 6, 8, 12, 8, 12, 15, 6, 8, 12, 12, 6, 16, 6, 10, 18, 8, 6, 14, 9, 12, 12, 10, 6, 16, 12, 12, 12, 8, 6, 20, 6, 8, 18, 9, 12, 16, 6, 10, 12, 16, 6, 18, 6, 8, 18, 10

Offset

1,1

Links

Table of n, a(n) for n=1..76.

Vaclav Kotesovec, Graph - the asymptotic ratio (100000 terms)

Formula

For n > 1, a(n) = A366872(n-2).

Sum_{k=1..n} a(k) ~ (8*n*(log(n) + 2*gamma - 1) + n*4*log(2)) / 4, where gamma is the Euler-Mascheroni constant A001620.

Mathematica

Table[DivisorSigma[0, 4*n], {n, 1, 150}]

Crossrefs

Cf. A193553, A366872.

Cf. A000005, A099777, A372713, A372785, A372786, A372787, A372788, A372789, A372790, A372791, A372792.

Sequence in context: A047840 A037189 A083342 * A016655 A057757 A379348

Adjacent sequences: A372781 A372782 A372783 * A372785 A372786 A372787

Keyword

nonn

Author

Vaclav Kotesovec, May 13 2024

Status

approved