A040088 Primes p such that x^3 = 21 has no solution mod p.

19, 31, 37, 61, 67, 97, 103, 109, 127, 139, 151, 157, 181, 193, 199, 211, 223, 271, 307, 313, 331, 337, 373, 379, 397, 409, 421, 463, 487, 499, 523, 541, 547, 571, 577, 601, 607, 613, 619, 643, 673, 709, 727

Offset

1,1

Comments

Complement of A040087 relative to A000040. - Vincenzo Librandi, Sep 17 2012

Links

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

Mathematica

ok[p_]:= Reduce[Mod[x^3 - 21, p] == 0, x, Integers] == False; Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 17 2012  *)

Prog

(Magma) [p: p in PrimesUpTo(1000) | not exists{x : x in ResidueClassRing(p) | x^3 eq 21} ]; // Vincenzo Librandi, Sep 17 2012

Crossrefs

Sequence in context: A339465 A279192 A159043 * A178251 A335418 A164320

Adjacent sequences: A040085 A040086 A040087 * A040089 A040090 A040091

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved