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A059310 Primes p such that x^21 = 2 has no solution mod p. 2
7, 13, 19, 29, 37, 43, 61, 67, 71, 73, 79, 97, 103, 113, 127, 139, 151, 163, 181, 193, 197, 199, 211, 239, 241, 271, 281, 313, 331, 337, 349, 367, 373, 379, 409, 421, 449, 463, 487, 491, 523, 541, 547, 571, 577, 607, 613, 617, 619, 631, 659, 661, 673, 701 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A049553 relative to A000040.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

ok[p_] := Reduce[Mod[x^21 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[150]], ok] (* Vincenzo Librandi, Sep 20 2012 *)

PROG

(MAGMA) [p: p in PrimesUpTo(710) | not exists{x: x in ResidueClassRing(p) | x^21 eq 2}]; // Vincenzo Librandi, Sep 20 2012

CROSSREFS

Cf. A000040, A049553.

Sequence in context: A211431 A096452 A059647 * A101324 A216830 A129904

Adjacent sequences:  A059307 A059308 A059309 * A059311 A059312 A059313

KEYWORD

nonn,easy

AUTHOR

Klaus Brockhaus, Jan 25 2001

STATUS

approved

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Last modified December 18 19:05 EST 2014. Contains 252174 sequences.