%I A006032 M2670
%S A006032 3,7,19,31,41,2687,19697
%N A006032 Numbers n such that (14^n - 1)/13 is prime.
%D A006032 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006032 H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
%H A006032 H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">
               Mersenne and Fermat primes field</a>
%t A006032 lst={};Do[If[PrimeQ[(14^n-1)/13], Print[n];AppendTo[lst, n]], {n, 10^5}];
               lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 21 2008]
%Y A006032 Sequence in context: A056725 A091738 A136054 this_sequence A066148 A093932 
               A141173
%Y A006032 Adjacent sequences: A006029 A006030 A006031 this_sequence A006033 A006034 
               A006035
%K A006032 hard,nonn
%O A006032 1,1
%A A006032 N. J. A. Sloane (njas(AT)research.att.com).
%E A006032 One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 
               2008