OFFSET
1,1
COMMENTS
Primes of the form 5x^2+2xy+5y^2, with x and y any integer. Discriminant=-96. Also primes of the forms 5x^2+4xy+20y^2 and 5x^2+2xy+29y^2. See A140633. - T. D. Noe, May 19 2008
Also primes of the form -4*x^2+4*x*y+5*y^2, of discriminant -96 (as well as of the form 8*x^2+16*x*y+5*y^2). - Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 28 2008
REFERENCES
Z. I. Borevich and I. R. Shafarevich. Number Theory. Academic Press. 1966.
LINKS
Vincenzo Librandi and Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi]
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
FORMULA
a(n) ~ 8n log n. - Charles R Greathouse IV, Dec 07 2014
EXAMPLE
29 is a member because we can write 29=-4*4^2+4*4*3+5*3^2 (or 29=8*1^2+16*1*1+5*1^2).
MATHEMATICA
Union[QuadPrimes2[5, 2, 5, 10000], QuadPrimes2[5, -2, 5, 10000]] (* see A106856 *)
PROG
(PARI) select(n->n%24==5, primes(1000)) \\ Charles R Greathouse IV, Dec 07 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 09 2005
EXTENSIONS
Name and comment switched by Charles R Greathouse IV, Dec 07 2014
Edited by N. J. A. Sloane, Jul 14 2019
STATUS
approved