A246456 a(n) = sigma(n + sigma(n)).

3, 6, 8, 12, 12, 39, 24, 24, 36, 56, 24, 90, 40, 60, 56, 48, 48, 80, 56, 96, 54, 90, 48, 224, 120, 126, 68, 224, 60, 216, 104, 120, 121, 180, 84, 128, 124, 171, 120, 252, 84, 288, 120, 255, 168, 180, 120, 308, 162, 168, 168, 372, 108, 360, 128, 372, 138, 266

Offset: 1

Author

Jaroslav Krizek, Sep 07 2014

Keywords

• nonn

Examples

			For n = 6; a(n) = sigma(6 + sigma(6)) = sigma(18) = 39.
		

Crossrefs

Cf. A000203, A246909, A246907 (numbers n such that a(n) = 3n), A246915 (numbers n such that a(n) = a(n+1)).

Cf. Sequences of numbers n such that a(n) = k*sigma(n):

A246857 (k=2), A246910 (k=3), A246911 (k=4), A246912 (k=5), A246913 (k=6).

Programs

Magma

[SumOfDivisors(n+SumOfDivisors(n)):n in[1..1000]]

PARI

vector(100,n,sigma(n+sigma(n))) \\ Derek Orr, Sep 07 2014