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%I #16 Aug 04 2020 12:23:46
%S 19,269,349,383,1303,15031,200443
%N Numbers n such that (48^n - 1)/47 is prime.
%C a(7) > 10^5.
%C All terms are prime.
%H Harvey Dubner, <a href="http://dx.doi.org/10.1090/S0025-5718-1993-1185243-9">Generalized repunit primes</a>, Math. Comp., 61 (1993), 927-930.
%H Henri Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>
%p A245237:=n->`if`(isprime((48^n - 1)/47), n, NULL); seq(A245237(n), n=1..100000); # _Wesley Ivan Hurt_, Apr 12 2014
%t Select[Prime[Range[100000]], PrimeQ[(48^# - 1)/47] &]
%o (PARI) is(n)=ispseudoprime((48^n-1)/47) \\ _Charles R Greathouse IV_, Jun 06 2017
%Y Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035, A127995, A127996, A127997, A127998, A127999, A098438, A128002, A128003, A128004, A128005, A240765, A242797, A243279.
%K hard,more,nonn
%O 1,1
%A _Robert Price_, Jul 14 2014
%E a(7) corresponds to a probable prime discovered by _Paul Bourdelais_, Aug 04 2020
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