A049555 - OEIS

%I #15 Sep 08 2022 08:44:58

%S 2,3,5,7,11,13,17,19,23,29,31,37,41,43,53,59,61,67,71,73,79,83,89,97,

%T 101,103,107,109,113,127,131,137,149,151,157,163,167,173,179,181,191,

%U 193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,281,283

%N Primes p such that x^23 = 2 has a solution mod p.

%C Complement of A040984 relative to A000040. - _Vincenzo Librandi_, Sep 14 2012

%H R. J. Mathar, <a href="/A049555/b049555.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Pri#smp">Index entries for related sequences</a>

%t ok[p_]:= Reduce[Mod[x^23 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[150]], ok] (* _Vincenzo Librandi_, Sep 14 2012 *)

%o (Magma) [p: p in PrimesUpTo(300) | exists(t){x : x in ResidueClassRing(p) | x^23 eq 2}]; // _Vincenzo Librandi_, Sep 14 2012

%Y Cf. A000040, A040984.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_