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A040138
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Primes p such that x^4 = 17 has a solution mod p.
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2
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2, 17, 19, 43, 47, 59, 67, 83, 103, 127, 149, 151, 157, 179, 191, 223, 229, 239, 251, 257, 263, 271, 293, 307, 331, 353, 359, 383, 389, 409, 433, 443, 457, 463, 467, 491, 509, 523, 563, 587, 599, 613, 631, 647
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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ok [p_]:=Reduce[Mod[x^4 - 17, p]== 0, x, Integers]=!= False; Select[Prime[Range[180]], ok] (* Vincenzo Librandi, Sep 12 2012 *)
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PROG
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(Magma) [p: p in PrimesUpTo(800) | exists{x: x in ResidueClassRing(p) | x^4 eq 17}]; // Vincenzo Librandi, Sep 12 2012
(PARI) /* with workaround for bug with ispower( Mod(17, n), 4) "division by zero" */
select( n->(n==2) || (ispower( Mod(17, n), 4)), primes(1000) )
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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