A029718 Numbers of form 2x^2 + 2xy + 3y^2.

0, 2, 3, 7, 8, 10, 12, 15, 18, 23, 27, 28, 32, 35, 40, 42, 43, 47, 48, 50, 58, 60, 63, 67, 72, 75, 82, 83, 87, 90, 92, 98, 103, 107, 108, 112, 115, 122, 123, 127, 128, 135, 138, 140, 147, 160, 162, 163, 167, 168, 172, 175, 178, 183, 188, 192, 200, 202, 203, 207, 210

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Numbers represented by quadratic form with Gram matrix [ 2, 1; 1, 3 ].

References

• H. Cohn, A second course in number theory, John Wiley & Sons, Inc., New York-London, 1962. see page 3.

Links

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

Crossrefs

Cf. A028927.

For primes see A106865.

For the properly represented numbers see A344232.

Formula

List contains 0 and all positive n such that 2*A035170(n) = A028586(n) is nonzero. - Michael Somos, Oct 21 2006

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Mar 29 2000