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A140615
Primes of the form 13x^2+6xy+21y^2.
2
13, 61, 109, 277, 349, 373, 541, 613, 733, 853, 877, 997, 1069, 1117, 1381, 1429, 1597, 1669, 1693, 1789, 1861, 1933, 2053, 2221, 2389, 2437, 2749, 2917, 3109, 3181, 3229, 3253, 3373, 3517, 3541, 3637, 3709, 4021, 4549, 4597, 4813, 4861
OFFSET
1,1
COMMENTS
Discriminant=-1056. Also primes of the form 13x^2+2xy+61y^2.
In base 12, the sequence is 11, 51, 91, 1E1, 251, 271, 391, 431, 511, 5E1, 611, 6E1, 751, 791, 971, 9E1, E11, E71, E91, 1051, 10E1, 1151, 1231, 1351, 1471, 14E1, 1711, 1831, 1971, 1X11, 1X51, 1X71, 1E51, 2051, 2071, 2131, 2191, 23E1, 2771, 27E1, 2951, 2991, where X is 10 and E is 11. Moreover, the discriminant is -740. - Walter Kehowski, May 31 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[13, 6, 21, 10000], QuadPrimes2[13, -6, 21, 10000]] (* see A106856 *)
CROSSREFS
Cf. A140633.
Sequence in context: A028874 A087106 A142402 * A086361 A119151 A081589
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 19 2008
STATUS
approved