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A059664 Primes p such that x^18 = 2 has no solution mod p, but x^6 = 2 has a solution mod p. 3
433, 919, 1423, 1999, 2017, 2143, 2287, 2791, 2953, 3457, 3889, 4177, 4519, 4663, 5113, 5167, 6679, 6967, 8713, 9631, 9649, 9721, 10009, 11863, 12241, 12583, 12799, 13177, 13591, 15913, 16057, 16111, 16561, 16921, 17551, 18127, 18793, 19081 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..340

MATHEMATICA

Select[Prime[Range[PrimePi[20000]]], !MemberQ[PowerMod[Range[#], 18, #], Mod[2, #]] && MemberQ[PowerMod[Range[#], 6, #], Mod[2, #]]&] (* Vincenzo Librandi, Sep 21 2013 *)

PROG

(MAGMA) [p: p in PrimesUpTo(20000) | not exists{x: x in ResidueClassRing(p) | x^18 eq 2} and exists{x: x in ResidueClassRing(p) | x^6 eq 2}]; // Vincenzo Librandi, Sep 21 2012

CROSSREFS

A000040, A040992, A040993, A049550, A059665.

Sequence in context: A165503 A142539 A059665 * A289857 A198450 A241925

Adjacent sequences:  A059661 A059662 A059663 * A059665 A059666 A059667

KEYWORD

nonn,easy

AUTHOR

Klaus Brockhaus, Feb 04 2001

STATUS

approved

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Last modified May 9 00:09 EDT 2021. Contains 343685 sequences. (Running on oeis4.)