A163163 a(n) = sigma(n) + tau(n) - n.

1, 3, 3, 6, 3, 10, 3, 11, 7, 12, 3, 22, 3, 14, 13, 20, 3, 27, 3, 28, 15, 18, 3, 44, 9, 20, 17, 34, 3, 50, 3, 37, 19, 24, 17, 64, 3, 26, 21, 58, 3, 62, 3, 46, 39, 30, 3, 86, 11, 49, 25, 52, 3, 74, 21, 72, 27, 36, 3, 120, 3, 38, 47, 70, 23, 86, 3, 64, 31, 82, 3, 135, 3, 44, 55, 70, 23, 98, 3

Offset: 1

Author

Juri-Stepan Gerasimov, Jul 22 2009

Keywords

• nonn
• easy

Examples

			a(10) = A007503(10) - 10 = 22 - 10 = 12.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Antti Karttunen, Sequence plotted up to n=10000, showing the details better

Crossrefs

Cf. A000005, A000027, A000203, A001065, A007503.

Programs

Mathematica

Table[Apply[Plus, DivisorSigma[#, n] & /@ {0, 1}] - n, {n, 79}] (* Michael De Vlieger, Feb 25 2018 *)

PARI

A163163(n) = (sigma(n)+numdiv(n)-n); \\ Antti Karttunen, Feb 25 2018

Formula

a(n) = A007503(n) - n = A000203(n) + A000005(n) - n.

a(n) = A000005(n) + A001065(n). - Antti Karttunen, Feb 25 2018

Extensions

47 replaced with 37 by R. J. Mathar, Jul 25 2009