OFFSET
1,1
COMMENTS
Discriminant = -63.
This appears to coincide with the sequence of primes of the form x^2 + 63y^2. - Artur Jasinski, Apr 24 2008
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)
MATHEMATICA
QuadPrimes2[1, -1, 16, 10000] (* see A106856 *)
PROG
(PARI) {a(n)= local(m, c, x); if(n<1, 0, c=0; m=1; while( c<n, m++; if( isprime(m), for(x=0, sqrtint(m\7), if(issquare(m-7*x^2), if( x%3==0, c++); break)))); m)} /* Michael Somos, May 28 2005 */
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 09 2005
STATUS
approved