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%I #17 Sep 08 2022 08:44:58
%S 2,23,31,47,71,89,127,167,191,223,233,239,257,263,311,359,383,431,439,
%T 479,503,599,601,647,719,727,743,839,863,881,887,911,919,983,1031,
%U 1103,1151,1223,1289,1319,1327,1367,1399,1423,1433,1439,1471,1487,1511,1559
%N Primes p such that x^48 = 2 has a solution mod p.
%C Complement of A212376 relative to A000040. - _Vincenzo Librandi_, Sep 14 2012
%H R. J. Mathar, <a href="/A049580/b049580.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^48 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[300]], ok] (* _Vincenzo Librandi_, Sep 14 2012 *)
%o (Magma) [p: p in PrimesUpTo(1600) | exists(t){x : x in ResidueClassRing(p) | x^48 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,2,48),print1(p,", ")));
%o /* _Joerg Arndt_, Sep 21 2012 */
%Y Cf. A000040, A212376.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_
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