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A145041 Primes p (A000043) such that 2^p-1 is prime (A000668) and congruent to 31 mod 6! 7
5, 17, 89, 521, 4253, 9689, 9941, 11213, 19937, 21701, 859433, 1398269, 2976221, 3021377, 6972593, 32582657, 43112609 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Mersenne numbers (with exception first two) are congruent to 31, 127, 271, 607 mod 6!. This sequences is subset of A000043.

LINKS

Table of n, a(n) for n=1..17.

MATHEMATICA

p = {2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049, 216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667, 43112609}; a = {}; Do[If[Mod[2^p[[n]] - 1, 6! ] == 31, AppendTo[a, p[[n]]]], {n, 1, Length[p]}]; a (*Artur Jasinski*)

CROSSREFS

Cf. A000043, A000668, A124477, A139484, A145038, A112633, A145041, A145042, A145044, A145045, A145046.

Sequence in context: A012782 A026685 A089923 * A212291 A179684 A250744

Adjacent sequences:  A145038 A145039 A145040 * A145042 A145043 A145044

KEYWORD

nonn

AUTHOR

Artur Jasinski, Sep 30 2008

STATUS

approved

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Last modified August 18 16:13 EDT 2018. Contains 313833 sequences. (Running on oeis4.)