A249904 a(n) = mu(n) + sigma(n) - n.

1, 0, 0, 3, 0, 7, 0, 7, 4, 9, 0, 16, 0, 11, 10, 15, 0, 21, 0, 22, 12, 15, 0, 36, 6, 17, 13, 28, 0, 41, 0, 31, 16, 21, 14, 55, 0, 23, 18, 50, 0, 53, 0, 40, 33, 27, 0, 76, 8, 43, 22, 46, 0, 66, 18, 64, 24, 33, 0, 108, 0, 35, 41, 63, 20, 77

Offset

1,4

Comments

The 0 terms identify the prime numbers.

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = A001065(n) + A008683(n). - Antti Karttunen, Feb 25 2018

Mathematica

Table[(MoebiusMu[k] + (DivisorSigma[1, k] - k)), {k, 200} ]

Prog

(PARI) vector(100, n, moebius(n) + sigma(n) - n) \\ Michel Marcus, Jan 31 2015

Crossrefs

Cf. A000203, A001065, A008683.

Cf. A249767, A249901.

Sequence in context: A135534 A346516 A337767 * A324875 A266437 A077896

Adjacent sequences: A249901 A249902 A249903 * A249905 A249906 A249907

Keyword

nonn

Author

Ke Xiao, Jan 13 2015

Status

approved