A040987 Primes p such that x^5 = 21 has no solution mod p.

31, 41, 71, 101, 131, 151, 181, 191, 211, 241, 251, 271, 281, 311, 331, 401, 431, 491, 521, 541, 571, 701, 751, 761, 811, 821, 881, 911, 941, 971, 991, 1021, 1031, 1051, 1061, 1091, 1151, 1181, 1201, 1291, 1301, 1321, 1361, 1381, 1471

Offset

1,1

Comments

Complement of A040986 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^5 - 21, p] == 0, x, Integers] == False; Select[Prime[Range[300]], ok] (* Vincenzo Librandi, Sep 19 2012 *)

Prog

(Magma) [p: p in PrimesUpTo(1500) | not exists{x: x in ResidueClassRing(p) | x^5 eq 21}]; // Vincenzo Librandi, Sep 19 2012

Crossrefs

Sequence in context: A141180 A176371 A284531 * A040180 A158754 A140458

Adjacent sequences: A040984 A040985 A040986 * A040988 A040989 A040990

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved