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Search: id:A141337
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| A141337 |
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Primes of the form -2*x^2+6*x*y+7*y^2 (as well as of the form 14*x^2+22*x*y+7*y^2). |
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+0
3
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| 7, 11, 19, 23, 43, 67, 79, 83, 103, 107, 191, 199, 227, 251, 263, 283, 359, 367, 379, 383, 419, 431, 467, 479, 503, 523, 563, 571, 619, 631, 643, 659, 727, 743, 751, 787, 827, 839, 907, 911, 919, 971, 983
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OFFSET
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0,1
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COMMENT
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Discriminant = 92. Class = 2. Binary quadratic forms a*x^2+b*x*y+c*y^2 have discriminant d=b^2-4ac and gcd(a,b,c)=1
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REFERENCES
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Borevich and Shafaewich, Number Theory.
D. B. Zagier, Zetafunktionen und quadratische Koerper.
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EXAMPLE
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a(5)=43 because we can write 43=-2*10^2+6*10*3+7*3^2 (or 14*1^2+22*1*1+7*1^2).
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CROSSREFS
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Cf. A141336 (d=92).
Sequence in context: A002052 A129842 A065312 this_sequence A155048 A053403 A032672
Adjacent sequences: A141334 A141335 A141336 this_sequence A141338 A141339 A141340
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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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