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A185167
Primes of the form k*6^m +1 where k is a Mersenne prime (A000668) and m is an integer.
3
19, 43, 109, 1117, 3889, 40177, 139969, 326593, 839809, 4718557, 5038849, 5925313, 18874333, 52068097, 1088391169, 1874451457, 6115248577, 24461134273, 1410554953729, 2429289086977, 31701630016513, 118486616113153
OFFSET
1,1
EXAMPLE
(2^521-1)*6^959+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}}]]]
Union[Flatten[Table[Select[(2^MersennePrimeExponent[n]-1)6^Range[ 0, 20]+ 1, PrimeQ], {n, 20}]]] (* Harvey P. Dale, Aug 15 2021 *)
PROG
(Magma) // For the Mersenne prime 2^521-1, for example:
[n: n in [0..1000] | IsPrime((2^521-1)*6^n+1)];
CROSSREFS
Sequence in context: A054820 A165567 A205533 * A140619 A229765 A058829
KEYWORD
nonn
AUTHOR
Gilbert Mozzo, Feb 18 2011
EXTENSIONS
Partially edited by N. J. A. Sloane, Feb 19 2011
STATUS
approved