A216751 Primes p such that x^40 = -2 has no solution mod p.

5, 7, 11, 13, 17, 23, 29, 31, 37, 41, 47, 53, 61, 71, 73, 79, 89, 97, 101, 103, 109, 113, 127, 131, 137, 149, 151, 157, 167, 173, 181, 191, 193, 197, 199, 211, 223, 229, 233, 239, 241, 263, 269, 271, 277, 281, 293, 311, 313, 317, 331, 349, 353, 359, 367, 373, 383, 389, 397

Offset: 1

Author

Vincenzo Librandi, Sep 16 2012

Keywords

• nonn
• easy

Comments

Complement of A051089 relative to A000040.

Links

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

Crossrefs

Cf. A000040, A051089.

Programs

Magma

[p: p in PrimesUpTo(400) | not exists{x : x in ResidueClassRing(p) | x^40 eq -2} ];

Mathematica

ok[p_]:=Reduce[Mod[x^40 + 2, p] == 0, x, Integers] == False;Select[Prime[Range[200]], ok]