A015851 - OEIS

%I #14 Sep 08 2019 17:37:49

%S 1,2,3,4,6,7,9,11,14,15,18,20,34,36,38,39,52,63,70,84,85,97,100,111,

%T 116,130,146,150,153,162,174,180,182,196,207,216,220,222,231,247,372,

%U 427,429,468,490,505,507,608,612,700,702,741,742,748,775,855,861

%N Numbers k such that phi(k) | sigma(k + 8).

%t Select[Range[1, 999], Divisible[DivisorSigma[1, 8 + #], EulerPhi[#]] &] (* _David Nacin_, Mar 04 2012 *)

%o (PARI) is(n)=!(sigma(n+8)%eulerphi(n)) \\ _Charles R Greathouse IV_, Sep 25 2012

%K nonn

%O 1,2

%A _Robert G. Wilson v_