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

%I #15 Sep 08 2022 08:44:59

%S 2,3,11,19,59,67,73,83,89,107,131,139,163,179,227,233,251,257,283,307,

%T 331,347,353,419,443,467,499,523,563,571,577,587,593,601,619,643,683,

%U 691,739,787,811,859,881,907,937,947,971,1019,1033,1049,1091,1097,1123,1153,1163,1171,1187

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

%C Complement of A216745 relative to A000040. - _Vincenzo Librandi_, Sep 17 2012

%H Vincenzo Librandi, <a href="/A051083/b051083.txt">Table of n, a(n) for n = 1..1000</a>

%t ok[p_]:= Reduce[Mod[x^28 + 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[500]], ok] (* _Vincenzo Librandi_, Sep 15 2012 *)

%o (PARI) /* see A051071 */

%o (Magma) [p: p in PrimesUpTo(1200) | exists(t){x : x in ResidueClassRing(p) | x^28 eq - 2}]; // _Vincenzo Librandi_, Sep 15 2012

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_

%E More terms from _Joerg Arndt_, Jul 27 2011