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A145044 Primes p (A000043) such that 2^p-1 is prime (A000668) and congruent to 271 mod 6! 4
13, 61, 2281, 3217, 23209, 44497, 132049, 13466917, 30402457 (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..9.

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! ] == 271, AppendTo[a, p[[n]]]], {n, 1, Length[p]}]; a (*Artur Jasinski*)

CROSSREFS

A000043, A000668, A124477, A139484, A145038, A145039, A145041, A145042, A145044, A145045, A145046

Sequence in context: A257216 A135535 A158870 * A264612 A044151 A044532

Adjacent sequences:  A145041 A145042 A145043 * A145045 A145046 A145047

KEYWORD

nonn

AUTHOR

Artur Jasinski, Sep 30 2008

STATUS

approved

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Last modified September 23 15:54 EDT 2017. Contains 292361 sequences.