%I #20 Sep 08 2022 08:44:58
%S 2,3,5,11,17,23,29,31,41,43,47,53,59,71,83,89,101,107,109,113,127,131,
%T 137,149,157,167,173,179,197,223,227,233,239,251,257,263,269,277,281,
%U 283,293,307,311,317,347,353,359,383,389,397,401,431,433,439,443,449
%N Primes p such that x^57 = 2 has a solution mod p.
%C Complement of A059643 relative to A000040. - _Vincenzo Librandi_, Sep 14 2012
%H R. J. Mathar, <a href="/A049589/b049589.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^57 - 2, p] == 0, x, Integers] == True; Select[Prime[Range[100]], ok] (* _Vincenzo Librandi_, Sep 14 2012 *)
%o (Magma) [p: p in PrimesUpTo(500) | exists(t){x : x in ResidueClassRing(p) | x^57 eq 2}]; // _Vincenzo Librandi_, Sep 14 2012
%o (PARI)
%o N=10^4; default(primelimit,N);
%o ok(p, r, k)={ return ( (p==r) || (Mod(r,p)^((p-1)/gcd(k,p-1))==1) ); }
%o forprime(p=2,N, if (ok(p,2,57),print1(p,", ")));
%o /* _Joerg Arndt_, Sep 21 2012 */
%Y Cf. A000040, A059643.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_
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