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A140622
Primes of the form 21x^2+12xy+76y^2.
1
109, 229, 349, 421, 541, 661, 709, 1021, 1549, 1669, 1789, 1861, 2221, 2269, 2749, 3061, 3109, 3229, 3469, 3541, 4621, 4789, 4909, 5101, 5701, 5869, 6229, 6469, 6661, 6781, 6949, 7741, 7789, 8101, 8221, 8461, 8821, 9349, 9661, 9781, 9901
OFFSET
1,1
COMMENTS
Discriminant=-6240. Also primes of the form 45x^2+30xy+109y^2.
In base 12, the sequence is 91, 171, 251, 2E1, 391, 471, 4E1, 711, X91, E71, 1051, 10E1, 1351, 1391, 1711, 1931, 1971, 1X51, 2011, 2071, 2811, 2931, 2X11, 2E51, 3371, 3491, 3731, 38E1, 3X31, 3E11, 4031, 4591, 4611, 4831, 4911, 4X91, 5131, 54E1, 5711, 57E1, 5891, where X is for 10 and E is for 11. Moreover, the discriminant is -3740. - Walter Kehowski, Jun 01 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
Union[QuadPrimes2[21, 12, 76, 10000], QuadPrimes2[21, -12, 76, 10000]] (* see A106856 *)
CROSSREFS
Cf. A140633.
Sequence in context: A142697 A142777 A142797 * A278784 A256380 A063342
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 19 2008
STATUS
approved