A243173 Numbers of the form x^2+15y^2.

0, 1, 4, 9, 15, 16, 19, 24, 25, 31, 36, 40, 49, 51, 60, 61, 64, 69, 76, 79, 81, 85, 96, 100, 109, 115, 121, 124, 135, 136, 139, 141, 144, 151, 159, 160, 169, 171, 181, 184, 196, 199, 204, 211, 216, 225, 229, 235, 240, 241, 244, 249, 256, 265, 271, 276, 279, 285, 289, 304, 316, 321, 324, 331, 339, 340, 349, 360, 361, 375, 376, 379, 384, 391, 400, 409, 411

Offset: 1

Author

N. J. A. Sloane, Jun 01 2014

Keywords

• nonn

Comments

Discriminant -60.

Norms of numbers in Z[sqrt(-15)]. - Alonso del Arte, Sep 23 2014

Links

• Bruno Berselli, Table of n, a(n) for n = 1..1000
• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Crossrefs

Primes: A033212.

Programs

Mathematica

nn = 22; Union[Select[Flatten[Table[x^2 + 15 y^2, {x, 0, nn}, {y, 0, nn}]], # <= nn^2 &]] (* Bruno Berselli, Jun 02 2014 *)