A049560 - OEIS

A049560

Primes p such that x^28 = 2 has a solution mod p.

2, 7, 23, 31, 47, 73, 79, 89, 103, 151, 167, 191, 199, 223, 233, 257, 263, 271, 311, 353, 359, 367, 383, 431, 439, 479, 487, 503, 577, 593, 599, 601, 607, 631, 647, 719, 727, 751, 823, 839, 863, 881, 887, 919, 937, 983, 991, 1031, 1033, 1039, 1049, 1063, 1087

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OFFSET

1,1

COMMENTS

Complement of A059315 relative to A000040. - Vincenzo Librandi, Sep 14 2012

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

Index entries for related sequences

MATHEMATICA

ok[p_]:= Reduce[Mod[x^28 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 14 2012 *)

PROG

(Magma) [p: p in PrimesUpTo(1100) | exists(t){x : x in ResidueClassRing(p) | x^28 eq 2}]; // Vincenzo Librandi, Sep 14 2012