A042973 Primes p such that x^7 = 5 has no solution mod p.

29, 43, 113, 127, 197, 211, 239, 281, 337, 379, 421, 449, 463, 491, 547, 617, 631, 659, 673, 701, 743, 757, 911, 953, 967, 1009, 1051, 1093, 1163, 1289, 1373, 1429, 1471, 1499, 1583, 1597, 1667, 1709, 1723, 1877, 1933, 2003, 2017, 2087

Offset

1,1

Comments

Complement of A216882 relative to A000040. - Vincenzo Librandi, Sep 19 2012

Links

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

Mathematica

ok[p_]:= Reduce[Mod[x^7 - 5, p] == 0, x, Integers] == False; Select[Prime[Range[800]], ok] (* Vincenzo Librandi, Sep 19 2012  *)

Prog

(Magma) [p: p in PrimesUpTo(2500) | not exists{x : x in ResidueClassRing(p) | x^7 eq 5} ]; // Vincenzo Librandi, Sep 19 2012

Crossrefs

Sequence in context: A039348 A043171 A043951 * A323628 A020997 A108280

Adjacent sequences: A042970 A042971 A042972 * A042974 A042975 A042976

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved