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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 (list; graph; refs; listen; history; text; internal format)
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: A040066 A279192 A159043 * A178251 A164320 A154418

Adjacent sequences:  A040085 A040086 A040087 * A040089 A040090 A040091

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified January 27 02:46 EST 2020. Contains 331291 sequences. (Running on oeis4.)