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A015845 Numbers n such that phi(n) | sigma(n + 7). 6

%I

%S 1,2,3,4,5,6,7,8,12,16,20,22,24,26,27,28,31,35,39,40,50,58,63,70,88,

%T 95,108,112,116,120,135,152,163,183,224,228,241,273,315,323,364,369,

%U 455,476,520,524,616,620,632,703,782,855,903,945,950,1008,1124,1188

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

%H Ivan Neretin, <a href="/A015845/b015845.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[3000], Divisible[DivisorSigma[1, 7 + #], EulerPhi[#]] &] (* David Nacin, Mar 03 2012 *)

%o (PARI) is(n)=!(sigma(n+7)%eulerphi(n)) \\ _Charles R Greathouse IV_, Sep 25 2012

%K nonn

%O 1,2

%A _Robert G. Wilson v_

%E a(1) = 1 added by _Ivan Neretin_, Feb 05 2017

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Last modified May 23 04:59 EDT 2019. Contains 323508 sequences. (Running on oeis4.)