A015792 Numbers k such that phi(k) + 3 | sigma(k).

12, 126, 152, 216, 245, 392, 490, 63872, 259856, 16750592, 4294541312

Offset: 1

Author

Robert G. Wilson v

Keywords

• nonn

Comments

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

Programs

Mathematica

Select[Range[100000],
Divisible[DivisorSigma[1, #], EulerPhi[#] + 3] &] (* David Nacin, Feb 28 2012 *)

Extensions

Offset corrected and a(8)-a(11) from Donovan Johnson, Feb 28 2012