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Search: id:A139602
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| A139602 |
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Primes of the form x^2+12*x*y-y^2. |
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+0
1
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| 37, 67, 107, 137, 139, 151, 233, 269, 293, 317, 349, 367, 491, 601, 691, 823, 839, 863, 877, 881, 929, 941, 971
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OFFSET
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1,1
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COMMENT
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Discriminant = 148. 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(4)=137 because we can write 137= 3^2+12*3*4-4^2
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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). A141161, A141162 (d=148).
Sequence in context: A121764 A131499 A054805 this_sequence A141163 A063461 A105462
Adjacent sequences: A139599 A139600 A139601 this_sequence A139603 A139604 A139605
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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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