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A049550
Primes p such that x^18 = 2 has a solution mod p.
6
2, 17, 23, 31, 41, 47, 71, 89, 113, 127, 137, 167, 191, 223, 233, 239, 257, 263, 281, 311, 353, 359, 383, 401, 431, 439, 449, 457, 479, 503, 521, 569, 593, 599, 601, 617, 641, 647, 719, 727, 743, 761, 809, 839, 857, 863, 881, 887, 911, 929, 953, 977, 983
OFFSET
1,1
COMMENTS
Coincides with sequence of primes p such that x^54 = 2 has a solution mod p for the first 167 terms (and then diverges).
MATHEMATICA
ok[p_]:= Reduce[Mod[x^18- 2, p] == 0, x, Integers]=!=False; Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 13 2012 *)
PROG
(PARI) forprime(p=2, 2000, if([]~!=polrootsmod(x^18-2, p), print1(p, ", "))); print();
/* Joerg Arndt, Jul 27 2011 */
(Magma) [p: p in PrimesUpTo(1000) | exists(t){x : x in ResidueClassRing(p) | x^18 eq 2}]; // Vincenzo Librandi, Sep 13 2012
CROSSREFS
Cf. A000040.
Sequence in context: A126961 A106622 A040992 * A049574 A018643 A094668
KEYWORD
nonn,easy
STATUS
approved