A137909 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, 2, 2, 3, 17, 8, 3, 6, 96, 9, 224, 33, 260, 1044, 2397, 3, 1487, 657, 9602, 2133, 18438, 93, 17273, 32583, 66539, 9632, 1431, 100440, 150857

Offset

1,2

Links

Table of n, a(n) for n=1..29.

Example

1*(2^2-1)*(1*(2^2-1)+1)+1=13 prime, 2^2-1 first Mersenne prime, a(1)=1
2*(2^3-1)*(2*(2^3-1)+1)+1=211 prime, 2^3-1 second Mersenne prime, a(2)=2

Crossrefs

Cf. A000043 (Mersenne exponents), A000668 (Mersenne primes).

Cf. A137906, A137907, A137908.

Sequence in context: A184840 A164022 A089751 * A035796 A049009 A101817

Adjacent sequences: A137906 A137907 A137908 * A137910 A137911 A137912

Keyword

hard,more,nonn

Author

Pierre CAMI, Feb 22 2008

Extensions

a(27)-a(29) by Pierre CAMI, Oct 11 2014

Status

approved