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A003626
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Inert rational primes in Q(sqrt(-5)).
(Formerly M4769)
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8
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11, 13, 17, 19, 31, 37, 53, 59, 71, 73, 79, 97, 113, 131, 137, 139, 151, 157, 173, 179, 191, 193, 197, 199, 211, 233, 239, 251, 257, 271, 277, 293, 311, 313, 317, 331, 337, 353, 359, 373, 379, 397, 419, 431, 433, 439, 457, 479, 491, 499, 557, 571, 577, 593, 599
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OFFSET
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1,1
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COMMENTS
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Primes congruent to 11, 13, 17, 19 (mod 20). - Michael Somos, Aug 14 2012
Legendre symbol (-5, a(n)) = -1. For prime 5 this symbol is set to 0, and for other odd primes (-5, prime) = +1, given in A139513. - Wolfdieter Lang, Mar 05 2021
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REFERENCES
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H. Hasse, Number Theory, Springer-Verlag, NY, 1980, p. 498.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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MATHEMATICA
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Select[Prime[Range[1000]], MemberQ[{11, 13, 17, 19}, Mod[#, 20]]&] (* Vincenzo Librandi, Aug 20 2012 *)
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PROG
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(PARI) {a(n) = local( cnt, m ); if( n<1, return( 0 )); while( cnt < n, if( isprime( m++) && kronecker( -20, m )==-1, cnt++ )); m} /* Michael Somos, Aug 14 2012 */
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CROSSREFS
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KEYWORD
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nonn,nice
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AUTHOR
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STATUS
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approved
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