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Primes p such that x^16 = -2 has no solution mod p.
2

%I #12 Mar 19 2023 13:33:57

%S 5,7,13,17,23,29,31,37,41,47,53,61,71,73,79,89,97,101,103,109,113,127,

%T 137,149,151,157,167,173,181,191,193,197,199,223,229,233,239,241,263,

%U 269,271,277,293,311,313,317,337,349,353,359,367,373,383,389,397

%N Primes p such that x^16 = -2 has no solution mod p.

%C Complement of A051077 relative to A000040.

%H Vincenzo Librandi, <a href="/A216739/b216739.txt">Table of n, a(n) for n = 1..1000</a>

%t ok[p_] := Reduce[Mod[x^16 + 2, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok]

%o (Magma) [p: p in PrimesUpTo(400) | forall{x: x in ResidueClassRing(p) | x^16 ne -2}]; // _Bruno Berselli_, Sep 20 2012

%o (PARI) select(x->!ispower(Mod(-2, x), 16), primes(100)) \\ _Michel Marcus_, Mar 19 2023

%Y Cf. A000040, A051077.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Sep 15 2012