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A040112 Primes p such that x^4 = 7 has a solution mod p. 2
2, 3, 7, 19, 29, 31, 37, 47, 59, 83, 103, 109, 113, 131, 139, 167, 193, 199, 223, 227, 251, 271, 283, 307, 311, 367, 383, 389, 419, 439, 449, 457, 467, 479, 503, 523, 563, 587, 607, 613, 619, 643, 647, 653, 691 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

ok [p_]:=Reduce[Mod[x^4- 7, p] == 0, x, Integers] =!= False;  Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 11 2012 *)

PROG

(MAGMA) [p: p in PrimesUpTo(800) | exists(t){x : x in ResidueClassRing(p) | x^4 eq 7}]; // Vincenzo Librandi, Sep 11 2012

CROSSREFS

Sequence in context: A218100 A078373 A038878 * A246373 A074855 A038935

Adjacent sequences:  A040109 A040110 A040111 * A040113 A040114 A040115

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified April 8 03:01 EDT 2020. Contains 333312 sequences. (Running on oeis4.)