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Search: id:A141169
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| A141169 |
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Primes of the form 11*x^2+9*x*y-4*y^2. |
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+0
6
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| 2, 11, 13, 17, 23, 29, 31, 59, 73, 79, 89, 137, 139, 173, 199, 211, 223, 239, 283, 293, 307, 317, 349, 373, 379, 397, 401, 433, 457, 479, 491, 503, 523, 563, 571, 593, 613, 647, 673, 683, 701, 709, 719, 727, 769, 773, 787, 797, 829, 839, 887, 911, 967
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OFFSET
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1,1
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COMMENT
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Discriminant = 257. Class = 3. 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(3)=13 because we can write 13= 11*1^2+9*1*2-4*2^2
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CROSSREFS
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Cf. A038872 (d=5). A141131 (d=8). A141122, A141123 (d=12). A038883 (d=13). A038889 (d=17). A141111, A141112 (d=65). A141167, A141168 (d=257).
Sequence in context: A137977 A160950 A141168 this_sequence A079132 A023257 A068807
Adjacent sequences: A141166 A141167 A141168 this_sequence A141170 A141171 A141172
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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 (sergarmor(AT)yahoo.es), Jun 12 2008
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