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A141339 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). 2
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, 1013, 1019, 1049, 1091, 1097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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.

REFERENCES

Z. I. Borevich and I. R. Shafarevich, Number Theory.

D. B. Zagier, Zetafunktionen und quadratische Koerper.

LINKS

Table of n, a(n) for n=1..52.

EXAMPLE

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).

CROSSREFS

Cf. A141338 (d=93).

Sequence in context: A056983 A175073 A062284 * A069348 A165561 A038960

Adjacent sequences:  A141336 A141337 A141338 * A141340 A141341 A141342

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

More terms from Colin Barker, Apr 05 2015

STATUS

approved

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Last modified October 29 18:30 EDT 2020. Contains 338067 sequences. (Running on oeis4.)