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Search: id:A141177
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| A141177 |
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Primes of the form -2*x^2+3*x*y+3*y^2 (as well as of the form 4*x^2+7*x*y+y^2). |
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+0
7
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| 3, 31, 37, 67, 97, 103, 157, 163, 181, 199, 223, 229, 313, 331, 367, 379, 397, 421, 433, 463, 487, 499, 577, 619, 631, 643, 661, 691, 709, 727, 751, 757, 823, 829, 859, 883, 907, 991
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OFFSET
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1,1
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COMMENT
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Discriminant = 33. 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(2)=31 because we can write 31=-2*4^2+3*4*3+3*3^2 (or 31=4*2^2+7*2*1+1^2)
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CROSSREFS
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Cf. A141176 (d=33) A038872 (d=5). A141131 (d=8). A141122, A141123 (d=12). A038883 (d=13). A038889 (d=17): A141111, A141112 (d=65).
Sequence in context: A042477 A023297 A077546 this_sequence A154502 A046282 A045709
Adjacent sequences: A141174 A141175 A141176 this_sequence A141178 A141179 A141180
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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 (marcanmar(AT)alum.us.es), Jun 12 2008
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