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A141339
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Primes of the form -x^2+9*x*y+3*y^2 (as well as of the form 11*x^2+15*x*y+3*y^2).
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2
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3, 11, 17, 23, 29, 53, 83, 89, 137, 167, 179, 197, 239, 251, 263, 269, 347, 353, 383, 389, 401, 449, 461, 491, 509, 557, 569, 587, 641, 647, 677, 719, 743, 761, 773, 797, 809, 821, 827, 863, 881, 911, 929, 941, 947, 953, 983, 1013, 1019, 1049, 1091, 1097
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OFFSET
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1,1
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COMMENTS
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Discriminant = 93. Class = 2. Binary quadratic forms a*x^2 + b*x*y + c*y^2 have discriminant d = b^2 - 4ac.
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REFERENCES
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Z. I. Borevich and I. R. Shafarevich, Number Theory.
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LINKS
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EXAMPLE
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a(5) = 29 because we can write 29 = -1^2 + 9*1*2 + 3*2^2 (or 29 = 11*1^2 + 15*1*1 + 3*1^2).
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 25 2008
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EXTENSIONS
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STATUS
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approved
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