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Search: id:A141339
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| A141339 |
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Primes of the form -x^2+9*x*y+3*y^2 (as well as of the form 11*x^2+15*x*y+3*y^2). |
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+0
3
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| 3, 11, 17, 23, 29, 53, 83, 89, 137, 167, 179, 197, 239, 251, 263, 269, 347, 353, 383, 389, 401, 449, 461, 491, 509, 557, 569, 587, 641, 647, 677, 719, 743, 761, 773, 797, 809, 821, 827, 863, 881, 911, 929, 941, 947, 953, 983
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Discriminant = 93. 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)=29 because we can write 29=-1^2+9*1*2+3*2^2 (or 29=11*1^2+15*1*1+3*1^2).
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CROSSREFS
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Cf. A141338 (d=93).
Sequence in context: A075334 A056983 A062284 this_sequence A069348 A038960 A019397
Adjacent sequences: A141336 A141337 A141338 this_sequence A141340 A141341 A141342
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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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