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%I #14 Sep 08 2019 18:16:23
%S 14,23,38,109,248,280,380,406,506,1178,1288,1364,1504,1528,1798,1976,
%T 1978,1990,2408,2528,2698,3160,3230,4318,4888,6106,6904,7160,7192,
%U 7366,8234,8648,8804,8920,8932,9238,10726,10856,11210,11684,11818,12008,12154,14212
%N Numbers k such that phi(k + 12) | sigma(k) for k not congruent to 0 (mod 3).
%t Select[Range[1, 10000], Divisible[DivisorSigma[1, #], EulerPhi[12 + #]] && !Mod[#, 3] == 0 &] (* _David Nacin_, Mar 04 2012 *)
%o (PARI) is(n)=n%3 && sigma(n)%eulerphi(n+12)==0 \\ _Charles R Greathouse IV_, Sep 25 2012
%K nonn
%O 1,1
%A _Robert G. Wilson v_
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