A059664 - OEIS

A059664

Primes p such that x^18 = 2 has no solution mod p, but x^6 = 2 has a solution mod p.

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

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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