%I #9 Sep 08 2022 08:45:02
%S 3,5,11,13,17,19,29,37,41,43,53,59,61,67,71,83,97,101,107,109,113,127,
%T 131,137,139,149,157,163,173,179,181,193,197,211,227,229,239,241,251,
%U 269,277,281,283,293,307,313,317,331,337,347,349,373,379,389,397,401
%N Primes p such that x^28 = 2 has no solution mod p.
%C Coincides for the first 51 terms with sequence A059634 of primes p such that x^56 = 2 has no solution mod p (first divergence is at 353, cf. A059635 ).
%C Complement of A049560 relative to A000040.
%H Vincenzo Librandi, <a href="/A059315/b059315.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[100]], ok ] (* _Vincenzo Librandi_, Sep 20 2012 *)
%o (Magma) [p: p in PrimesUpTo(405) | not exists{x : x in ResidueClassRing(p) | x^28 eq 2} ]; // _Vincenzo Librandi_, Sep 20 2012
%Y A000040, A049560, A059634, A059635.
%K nonn,easy
%O 1,1
%A _Klaus Brockhaus_, Jan 25 2001