A139508 Primes of the form x^2 + 28x*y + y^2 for x and y nonnegative.

61, 181, 601, 829, 1069, 1249, 1381, 1429, 1609, 1621, 1741, 2029, 2089, 2161, 2341, 2389, 2521, 3121, 3169, 3181, 3301, 3709, 3769, 4021, 4261, 4549, 4729, 4801, 4861, 4969, 5209, 5281, 5521, 5581, 5641, 5749, 5821, 6301, 6361, 6421, 6529, 6709, 6829

Offset: 1

Author

Artur Jasinski, Apr 24 2008

Keywords

• nonn

Comments

In base 12, the sequence is 51, 131, 421, 591, 751, 881, 971, 9E1, E21, E31, 1011, 1211, 1261, 1301, 1431, 1471, 1561, 1981, 1X01, 1X11, 1XE1, 2191, 2221, 23E1, 2571, 2771, 28X1, 2941, 2991, 2X61, 3021, 3081, 3241, 3291, 3321, 33E1, 3451, 3791, 3821, 3871, 3941, 3X71, 3E51, where X is 10 and E is 11. Moreover, the discriminant is 550. - Walter Kehowski, Jun 01 2008

Links

• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Crossrefs

Cf. A139489, A007645, A068228, A007519, A033212, A033212, A107152, A107008, A033215, A107145, A139490, A139491.

Programs

Mathematica

a = {}; w = 28; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)