A067349 Number of divisors of sigma(n)+phi(n).

2, 3, 4, 3, 4, 4, 4, 2, 2, 4, 4, 6, 4, 8, 6, 4, 4, 6, 4, 6, 6, 4, 4, 6, 4, 8, 4, 6, 4, 10, 4, 2, 6, 8, 12, 2, 4, 8, 10, 4, 4, 12, 4, 8, 8, 4, 4, 12, 6, 2, 8, 4, 4, 8, 10, 15, 6, 4, 4, 8, 4, 12, 12, 4, 12, 6, 4, 4, 12, 16, 4, 4, 4, 12, 6, 10, 12, 14, 4, 4, 6, 4, 4, 8, 6, 8, 10, 12, 4, 8, 8, 6, 6, 8

Offset: 1

Author

Labos Elemer, Jan 17 2002

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A000010, A000203, A011774, A067350, A067351.

Programs

Mathematica

Table[ DivisorSigma[ 0, DivisorSigma[ 1, w ]+EulerPhi[ w ] ], {w, 1, 128} ]

PARI

a(n) = numdiv(sigma(n)+eulerphi(n)); \\ Michel Marcus, Aug 13 2019

Formula

a(n) = A000005(A000010(n) + A000203(n)).