A028927 Numbers represented by quadratic form with Gram matrix [ 3, 1; 1, 5 ].

0, 3, 5, 6, 10, 12, 13, 19, 20, 21, 24, 26, 27, 35, 38, 40, 42, 45, 48, 52, 54, 59, 61, 69, 70, 75, 76, 80, 83, 84, 90, 91, 96, 101, 104, 108, 115, 117, 118, 122, 125, 131, 133, 138, 139, 140, 147, 150, 152, 157, 160, 166, 168, 171, 173, 180, 181, 182, 189, 192

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Nonnegative integers of the form 3*x^2 + 2*x*y + 5*y^2, discriminant -56. - Ray Chandler, Jul 12 2014

Links

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

Formula

a(x_i, x_j) = 3*x_i^2 + 2*x_i*x_j + 5*x_j^2, for all x_i >= 0, x_j any integer.

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Mar 28 2000