A186687 Primes of the form k*6^m - 1, where k is a Mersenne prime (A000668) and m >= 0.

2, 17, 41, 107, 251, 647, 761, 1511, 23327, 27431, 139967, 3145721, 30233087, 35551871, 6530347007, 39182082047, 91424858111, 146766805631, 6847552083566591, 153558654482644991, 246511875008397311, 14215144014964850687

Offset

1,1

Comments

Twin of A185167.

Links

Table of n, a(n) for n=1..22.

Example

(2^1279-1)*6^1047-1 is prime.

Mathematica

Union[Flatten[Table[Select[p*6^Range[0, 30] - 1, # < 10^20 && PrimeQ[#] &], {p, {3, 7, 31, 127, 8191, 131071, 524287, 2147483647, 2305843009213693951}}]]]

Prog

(Magma)
[n: n in [0..3000] | IsPrime((2^1279-1)*6^n-1)];

Crossrefs

Cf. A186104, A186105, A185069, A185167.

Sequence in context: A045390 A289135 A072582 * A256145 A096172 A120745

Adjacent sequences: A186684 A186685 A186686 * A186688 A186689 A186690

Keyword

nonn

Author

Gilbert Mozzo, Feb 25 2011

Status

approved