%I A139424
%S A139424 1,1,1,1,1,43,1,41,53,91,317,317,43,1,37,3595,563,17239,911,11497,58501,
%T A139424 1259,10283,138569,72247,27733
%N A139424 Smallest number k such that M(n)^2-k*M(n)-1 is prime with M(n)= Mersenne 
               primes =A000668(n).
%C A139424 All primes certified using openpfgw_v12 from primeform group
%e A139424 3*3-1*3-1=5 prime 3=M(1)=2^2-1 so k(1)=1
%e A139424 7*7-1*7-1=41 prime 7=M(2)=2^3-1 so k(2)=1
%e A139424 31*31-1*31-1=929 prime 31=M(3)=2^5-1 so k(3)=1
%Y A139424 Cf. A000668, A139425, A139426, A139427, A139428, A139429, A139430, A139421.
%Y A139424 Sequence in context: A152508 A070177 A114786 this_sequence A051318 A036202 
               A107814
%Y A139424 Adjacent sequences: A139421 A139422 A139423 this_sequence A139425 A139426 
               A139427
%K A139424 hard,more,nonn
%O A139424 1,6
%A A139424 Pierre CAMI (pierrecami(AT)tele2.fr), Apr 21 2008