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A139855
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Primes of the form 4x^2+4xy+31y^2.
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4
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31, 79, 151, 199, 271, 439, 631, 751, 919, 991, 1039, 1231, 1279, 1399, 1471, 1759, 1831, 1879, 1951, 1999, 2239, 2311, 2551, 2671, 2719, 2791, 3079, 3271, 3319, 3391, 3511, 3559, 3631, 3919, 4111, 4159, 4231, 4519, 4591, 4639, 4759, 4831
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OFFSET
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1,1
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COMMENTS
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Discriminant = -480. See A139827 for more information.
Also primes of the form 15x^2+16y^2, which has discriminant = -960. - T. D. Noe, May 07 2008
Also primes of the form 16x^2+8xy+31y^2, which has discriminant = -1920. See A140633. - T. D. Noe, May 19 2008
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LINKS
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FORMULA
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The primes are congruent to {31, 79} (mod 120).
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MATHEMATICA
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QuadPrimes2[4, -4, 31, 10000] (* see A106856 *)
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PROG
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(Magma) [ p: p in PrimesUpTo(6000) | p mod 120 in {31, 79}]; // Vincenzo Librandi, Jul 29 2012
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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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