|
Search: id:A141773
|
|
|
| A141773 |
|
Primes of the form x^2+9*x*y-y^2 (as well as of the form 9*x^2+11*x*y+y^2). |
|
+0
3
|
|
| 19, 59, 89, 101, 149, 151, 179, 191, 229, 239, 251, 271, 281, 331, 349, 359, 389, 409, 421, 461, 491, 509, 569, 599, 631, 659, 661, 701, 739, 761, 769, 829, 859, 919, 971
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Discriminant = 85. 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
|
Borevich and Shafaewich, Number Theory.
D. B. Zagier, Zetafunktionen und quadratische Koerper.
|
|
EXAMPLE
|
a(1)=19 because we can write 19 = 1^2+9*1*3-3^2
|
|
CROSSREFS
|
Cf. A141772 (d=85).
Sequence in context: A041706 A042619 A141887 this_sequence A031375 A146351 A139920
Adjacent sequences: A141770 A141771 A141772 this_sequence A141774 A141775 A141776
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (sergarmor(AT)yahoo.es), Jul 04 2008
|
|
|
Search completed in 0.002 seconds
|
