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.

1, 1, 1, 1, 1, 4, 1, 27, 14, 34, 6, 132, 97, 1, 500, 1816, 1292, 136, 2445, 15, 1934, 5472, 1584, 2734, 21022, 5870

Offset

1,6

Links

Table of n, a(n) for n=1..26.

Example

1*(2^2-1)*(1*(2^2-1)-1)-1=5 prime, 2^2-1 first Mersenne prime, a(1)=1;
1*(2^3-1)*(1*(2^3-1)-1)-1=41 prime, 2^3-1 second Mersenne prime, a(2)=1.

Crossrefs

Cf. A137907, A137908, A137909.

Sequence in context: A367304 A095887 A225213 * A139051 A061692 A096206

Adjacent sequences: A137903 A137904 A137905 * A137907 A137908 A137909

Keyword

nonn,hard,more

Author

Pierre CAMI, Feb 22 2008

Status

approved