OFFSET
1,1
COMMENTS
Discriminant=-1056. Also primes of the form 7x^2 + 4xy + 76y^2.
In base 12, the sequence is 7, 67, X7, 107, 1X7, 307, 427, 647, 687, 747, 867, 927, 987, X07, X27, E67, 1027, 11X7, 1367, 13X7, 1467, 1547, 1587, 1647, 16X7, 1727, 1747, 1947, 1E07, 1E27, 2047, 2087, 20X7, 2107, 2267, 2287, 2367, 2467, 2547, 2787, 2827, 2847, where X is 10 and E is 11. Moreover, the discriminant is -740. - Walter Kehowski, Jun 01 2008
LINKS
Vincenzo Librandi, N. J. A. Sloane and Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi, next 5218 terms from N. J. A. Sloane]
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
J. Voight, Quadratic forms that represent almost the same primes, Math. Comp., Vol. 76 (2007), pp. 1589-1617. See Example 6.1. - N. J. A. Sloane, Jun 07 2014
FORMULA
These are exactly the primes congruent to one of 7, 79, 127, 151, or 175 (mod 264) [Voight]. - N. J. A. Sloane, Jun 07 2014
MATHEMATICA
Union[QuadPrimes2[7, 6, 39, 10000], QuadPrimes2[7, -6, 39, 10000]] (* see A106856 *)
PROG
(PARI) select(n-> n%264==7 || n%264==79 || n%264==127 || n%264==151 || n%264==175, primes(100000)) \\ N. J. A. Sloane, Jun 07 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 19 2008
EXTENSIONS
Incorrect Mathematica program deleted by N. J. A. Sloane, Jun 07 2014
STATUS
approved