A040150 Primes p such that x^4 = 21 has no solution mod p.

11, 13, 19, 23, 29, 31, 37, 41, 53, 61, 71, 73, 89, 97, 101, 103, 107, 113, 137, 139, 149, 157, 173, 179, 181, 191, 197, 199, 223, 229, 233, 239, 241, 257, 263, 271, 277, 281, 283, 293, 307, 313, 317, 347, 349

Offset

1,1

Comments

Complement of A040149 relative to A000040. - Vincenzo Librandi, Sep 18 2012

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

ok[p_]:= Reduce[Mod[x^4 - 21, p] == 0, x, Integers] == False; Select[Prime[Range[100]], ok] (* Vincenzo Librandi, Sep 18 2012  *)

Prog

(Magma) [p: p in PrimesUpTo(500) | not exists{x : x in ResidueClassRing(p) | x^4 eq 21} ]; // Vincenzo Librandi, Sep 18 2012

Crossrefs

Sequence in context: A030792 A101934 A164861 * A214629 A330696 A103803

Adjacent sequences: A040147 A040148 A040149 * A040151 A040152 A040153

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved