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A137906 Least k such that k*(2^p-1)*(k*(2^p-1)-1)-1 is prime, where 2^p-1 runs through the Mersenne primes. 3

%I

%S 1,1,1,1,1,4,1,27,14,34,6,132,97,1,500,1816,1292,136,2445,15,1934,

%T 5472,1584,2734,21022,5870

%N Least k such that k*(2^p-1)*(k*(2^p-1)-1)-1 is prime, where 2^p-1 runs through the Mersenne primes.

%e 1*(2^2-1)*(1*(2^2-1)-1)-1=5 prime, 2^2-1 first Mersenne prime, a(1)=1;

%e 1*(2^3-1)*(1*(2^3-1)-1)-1=41 prime, 2^3-1 second Mersenne prime, a(2)=1.

%Y Cf. A137907, A137908, A137909.

%K nonn,hard,more

%O 1,6

%A _Pierre CAMI_, Feb 22 2008

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Last modified September 24 15:40 EDT 2021. Contains 347643 sequences. (Running on oeis4.)