A079535 - OEIS

A079535

a(n) = phi(n)*d(n) - n.

0, 0, 1, 2, 3, 2, 5, 8, 9, 6, 9, 12, 11, 10, 17, 24, 15, 18, 17, 28, 27, 18, 21, 40, 35, 22, 45, 44, 27, 34, 29, 64, 47, 30, 61, 72, 35, 34, 57, 88, 39, 54, 41, 76, 99, 42, 45, 112, 77, 70, 77, 92, 51, 90, 105, 136, 87, 54, 57, 132, 59, 58, 153, 160, 127, 94, 65, 124, 107, 122, 69

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

COMMENTS

It is known that a(n) >= 0.

REFERENCES

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 10.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

MATHEMATICA

Table[EulerPhi[n]*DivisorSigma[0, n] - n, {n, 1, 80}] (* G. C. Greubel, Jan 14 2019 *)

PROG