A366621 - OEIS

A366621

Number of divisors of 6^n-1.

2, 4, 4, 8, 6, 16, 4, 16, 16, 48, 8, 128, 8, 48, 48, 64, 32, 128, 8, 384, 16, 32, 32, 512, 32, 128, 64, 384, 4, 1536, 8, 512, 64, 256, 96, 8192, 64, 64, 64, 3072, 8, 768, 32, 512, 1536, 256, 16, 8192, 32, 512, 512, 2048, 16, 2048, 96, 12288, 128, 64, 16

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OFFSET

1,1

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..420

FORMULA

a(n) = sigma0(6^n-1) = A000005(A024062(n)).

EXAMPLE

a(4)=8 because 6^4-1 has divisors {1, 5, 7, 35, 37, 185, 259, 1295}.

MAPLE

a:=n->numtheory[tau](6^n-1):

seq(a(n), n=1..100);