%I A102604
%S A102604 2,3,7,41,43,79,421
%N A102604 Numbers n such that ((2*n)^n-1)/(2*n-1) is prime.
%C A102604 The next n in the sequence is > 4261 if exists
%C A102604 Note that (b^n-1)/(b-1) is prime only if n is prime, so all the elements 
               in this sequence must be primes. - Marco Bodrato (marco2007(AT)bodrato.it), 
               Oct 31 2007
%e A102604 (((2*2)^2)-1)/(2*2-1) = 15/3 = 5 prime so a(1)=2
%Y A102604 Cf. A088790.
%Y A102604 Sequence in context: A000317 A047024 A037843 this_sequence A119662 A163157 
               A000945
%Y A102604 Adjacent sequences: A102601 A102602 A102603 this_sequence A102605 A102606 
               A102607
%K A102604 more,nonn
%O A102604 1,1
%A A102604 Pierre CAMI (pierrecami(AT)tele2.fr), Jan 29 2005