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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 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, A112633, 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 May 26 16:58 EDT 2018. Contains 304613 sequences. (Running on oeis4.)