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A106930
Primes of the form x^2 - xy + 16y^2, with x and y nonnegative.
2
67, 79, 127, 163, 277, 373, 421, 463, 541, 547, 571, 613, 631, 739, 823, 877, 967, 1009, 1033, 1051, 1087, 1093, 1129, 1213, 1297, 1579, 1621, 1663, 1723, 1831, 1933, 1999, 2011, 2179, 2251, 2269, 2293, 2377, 2389, 2437, 2503, 2557, 2683, 2689, 2731, 2767
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
Sequence in context: A044035 A124476 A066475 * A106929 A173040 A091490
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 09 2005
STATUS
approved