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Search: id:A141166
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| A141166 |
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Primes of the form x^2+15*x*y-y^2. |
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+0
8
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| 37, 53, 173, 193, 229, 241, 347, 359, 383, 439, 443, 449, 461, 503, 509, 541, 593, 607, 617, 619, 643, 691, 907, 967, 977
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OFFSET
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1,1
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COMMENT
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Discriminant = 229. 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(2)=53 because we can write 53= 3^2+15*3*1-1^2
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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). A141164, A141165 (d=229).
Adjacent sequences: A141163 A141164 A141165 this_sequence A141167 A141168 A141169
Sequence in context: A080906 A101940 A036540 this_sequence A139918 A108273 A045223
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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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