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%I #22 May 01 2023 09:21:13
%S 1,2,3,4,6,21,24,27,30,54,70,126,369,435,612,787,1275,2155,2436,5734,
%T 6016,16107,25786
%N Numbers k such that 6^k + 7 is prime.
%t Select[Range[10000], PrimeQ[6^# + 7] &]
%o (PARI) is(n)=ispseudoprime(6^n+7) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A145106, A217352.
%Y Cf. A104115 (associated primes).
%K nonn,more,hard
%O 1,2
%A _Vincenzo Librandi_, Oct 02 2012
%E a(20)-a(21) from _Bruno Berselli_, Oct 04 2012
%E a(22)-a(23) from _Michael S. Branicky_, Apr 30 2023
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