A015798 Numbers k such that phi(k) + 7 | sigma(k).

9, 18, 24, 408, 7684, 10848, 14528, 46272, 533776, 774912, 201142272, 1410521344, 3220488192, 4469373184, 6505814272, 27945013504

Offset: 1

Author

Robert G. Wilson v

Keywords

• nonn

Comments

a(17) > 10^12. - Donovan Johnson, Feb 28 2012

Programs

Mathematica

Cases[Range[100000],
x_ /; Divisible[DivisorSigma[1, x], EulerPhi[x] + 7] == True] (* David Nacin, Feb 28 2012 *)

Extensions

Offset corrected and a(9)-a(16) from Donovan Johnson, Feb 28 2012