A040147 Primes p such that x^4 = 20 has a solution mod p.

2, 5, 11, 19, 29, 31, 59, 61, 71, 79, 131, 139, 151, 179, 191, 199, 211, 229, 239, 251, 271, 311, 331, 349, 359, 379, 401, 409, 419, 421, 431, 439, 449, 479, 491, 499, 509, 521, 569, 571, 599, 619, 631, 659, 661

Offset

1,1

Links

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

Mathematica

ok [p_]:=Reduce[Mod[x^4 - 20, 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 20}]; // Vincenzo Librandi, Sep 12 2012

Crossrefs

Cf. A040148.

Sequence in context: A045363 A336116 A031870 * A152471 A088796 A190309

Adjacent sequences: A040144 A040145 A040146 * A040148 A040149 A040150

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved