A049560 - OEIS

A049560

Primes p such that x^28 = 2 has a solution mod p.

2, 7, 23, 31, 47, 73, 79, 89, 103, 151, 167, 191, 199, 223, 233, 257, 263, 271, 311, 353, 359, 367, 383, 431, 439, 479, 487, 503, 577, 593, 599, 601, 607, 631, 647, 719, 727, 751, 823, 839, 863, 881, 887, 919, 937, 983, 991, 1031, 1033, 1039, 1049, 1063, 1087

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Complement of A059315 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

EXAMPLE

0^28 == 2 (mod 2). 2^28 == 2 (mod 7). 4^28 == 2 (mod 23). 4^28 == 2 (mod 31). 19^28 == 2 (mod 47). 2^28 == 2 (mod 73). 30^28 == 2 (mod 79). 4^28 == 2 (mod 89). 20^28 == 2 (mod 103). - R. J. Mathar, Jul 20 2025

MATHEMATICA

ok[p_]:= Reduce[Mod[x^28 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 14 2012 *)

PROG

(Magma) [p: p in PrimesUpTo(1100) | exists(t){x : x in ResidueClassRing(p) | x^28 eq 2}]; // Vincenzo Librandi, Sep 14 2012

CROSSREFS

Cf. A000040, A059315.

Sequence in context: A072936 A049584 A045382 * A049588 A336786 A106020

Adjacent sequences: A049557 A049558 A049559 * A049561 A049562 A049563

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved