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A040088
Primes p such that x^3 = 21 has no solution mod p.
2
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
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
KEYWORD
nonn,easy
AUTHOR
STATUS
approved