A243654 Nonnegative numbers represented by the indefinite quadratic form 3x^2+5xy-3y^2, of discriminant 61.

0, 1, 3, 4, 5, 9, 12, 13, 15, 16, 19, 20, 25, 27, 36, 39, 41, 45, 47, 48, 49, 52, 57, 60, 61, 64, 65, 73, 75, 76, 80, 81, 83, 95, 97, 100, 103, 107, 108, 109, 113, 117, 121, 123, 125, 127, 131, 135, 137, 141, 144, 147, 149, 156, 163, 164, 167, 169, 171, 179, 180, 183, 188, 192, 195, 196, 197, 199

Offset: 1

Author

N. J. A. Sloane, Jun 10 2014

Keywords

• nonn

Comments

Also, nonnegative numbers represented by the indefinite quadratic form x^2-61y^2, of discriminant 244. The corresponding reduced form is x^2+14xy-12y^2.

Also 12*a(n) has the form z^2 - 61*y^2, where z = 6*x+5*y. [Bruno Berselli, Jun 20 2014]

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Crossrefs

For primes see A141215.

Programs

Maple

select(t -> nops([isolve(x^2-61*y^2=t)])>0,[$0..200]); # Robert Israel, Jun 11 2014