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%I #18 Jun 13 2017 14:25:07
%S 13,661,773,833,4273,40613
%N Numbers n such that 8^n - 7 is prime.
%C All terms are equal to 1/3 of the multiples of 3 in A059609.
%C Naturally these numbers are odd since (9-1)^(2n)-7 is divisible by 3. - _Bruno Berselli_, Oct 04 2012
%t Select[Range[4000], PrimeQ[8^# - 7] &]
%o (PARI) is(n)=ispseudoprime(8^n-7) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A059609, A217353, A217356.
%K nonn,more
%O 1,1
%A _Vincenzo Librandi_, Oct 02 2012
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