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A049587 Primes p such that x^55 = 2 has a solution mod p. 2
2, 3, 5, 7, 13, 17, 19, 29, 37, 43, 47, 53, 59, 73, 79, 83, 97, 103, 107, 109, 113, 127, 137, 139, 149, 151, 157, 163, 167, 173, 179, 193, 197, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 277, 283, 293, 307, 313, 317, 337, 347, 349, 359, 367, 373, 379 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A059642 relative to A000040. - Vincenzo Librandi, Sep 14 2012

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

Index entries for related sequences

MATHEMATICA

ok[p_] := Reduce[Mod[x^55 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[100]], ok] (* Vincenzo Librandi, Sep 14 2012 *)

PROG

(MAGMA) [p: p in PrimesUpTo(400) | exists(t){x : x in ResidueClassRing(p) | x^55 eq 2}]; // Vincenzo Librandi, Sep 14 2012

(PARI)

N=10^4;  default(primelimit, N);

ok(p, r, k)={ return ( (p==r) || (Mod(r, p)^((p-1)/gcd(k, p-1))==1) ); }

forprime(p=2, N, if (ok(p, 2, 55), print1(p, ", ")));

/* Joerg Arndt, Sep 21 2012 */

CROSSREFS

Cf. A000040, A059642.

Sequence in context: A133244 A077040 A153503 * A293008 A038903 A136003

Adjacent sequences:  A049584 A049585 A049586 * A049588 A049589 A049590

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified September 26 20:36 EDT 2020. Contains 337374 sequences. (Running on oeis4.)