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A106989
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Primes of the form x^2-xy+23y^2, with x and y nonnegative.
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3
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23, 29, 43, 53, 79, 107, 113, 127, 179, 191, 211, 233, 263, 277, 337, 347, 373, 389, 443, 491, 547, 569, 571, 599, 641, 653, 659, 673, 701, 751, 757, 809, 823, 883, 907, 911, 919, 953, 991, 1031, 1093, 1117, 1171, 1187, 1213, 1283, 1297, 1303, 1327
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OFFSET
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1,1
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COMMENTS
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Discriminant=-91.
Also, primes that are squares (mod 91), or equivalently, with Legendre symbols (p|7) = (p|13) = 1. Included as subsequence in A191054 which are primes with Jacobi symbol (p|7*13) = 1, including also primes with (p|7) = (p|13) = -1. - David Broadhurst and M. F. Hasler, Jan 15 2016
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LINKS
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MATHEMATICA
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QuadPrimes2[1, -1, 23, 10000] (* see A106856 *)
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PROG
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(PARI) is(p)=issquare(Mod(p, 91))&&isprime(p) \\ M. F. Hasler, Jan 15 2016
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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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