A040149 Primes p such that x^4 = 21 has a solution mod p.

2, 3, 5, 7, 17, 43, 47, 59, 67, 79, 83, 109, 127, 131, 151, 163, 167, 193, 211, 227, 251, 269, 311, 331, 337, 353, 373, 379, 383, 419, 463, 467, 479, 487, 499, 503, 509, 521, 547, 563, 571, 587, 593, 631, 647, 709

Offset

1,1

Links

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

Mathematica

ok [p_]:=Reduce[Mod[x^4 - 21, p]== 0, x, Integers]=!= False; Select[Prime[Range[180]], ok] (* Vincenzo Librandi, Sep 12 2012 *)

Prog

(Magma) [p: p in PrimesUpTo(800) | exists(t){x : x in ResidueClassRing(p) | x^4 eq 21}]; // Vincenzo Librandi, Sep 12 2012

Crossrefs

Cf. A040150.

Sequence in context: A141453 A100532 A231480 * A168034 A034970 A048417

Adjacent sequences: A040146 A040147 A040148 * A040150 A040151 A040152

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved