A015798 - OEIS

%I #16 Sep 08 2019 20:07:30

%S 9,18,24,408,7684,10848,14528,46272,533776,774912,201142272,

%T 1410521344,3220488192,4469373184,6505814272,27945013504

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

%C a(17) > 10^12. - _Donovan Johnson_, Feb 28 2012

%t Cases[Range[100000],

%t x_ /; Divisible[DivisorSigma[1, x], EulerPhi[x] + 7] == True] (* _David Nacin_, Feb 28 2012 *)

%K nonn

%O 1,1

%A _Robert G. Wilson v_

%E Offset corrected and a(9)-a(16) from _Donovan Johnson_, Feb 28 2012