A243186 Nonnegative integers of the form x^2 + 6xy - 5y^2.

0, 1, 2, 4, 8, 9, 11, 16, 18, 22, 25, 32, 35, 36, 43, 44, 49, 50, 64, 65, 67, 70, 72, 81, 86, 88, 91, 98, 99, 100, 107, 113, 121, 128, 130, 134, 137, 140, 144, 155, 162, 163, 169, 172, 176, 179, 182, 193, 196, 198, 200

Offset

1,3

Comments

Discriminant 56.

Nonnegative integers of the form 2x^2 - 7y^2. - Jon E. Schoenfield, Jun 03 2022

Links

Table of n, a(n) for n=1..51.

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

Mathematica

Reap[For[n = 0, n <= 200, n++, If[Reduce[1*x^2 + 6*x*y - 5*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]]

Crossrefs

Primes: A141190.

Sequence in context: A010071 A035271 A338047 * A326673 A297126 A044814

Adjacent sequences: A243183 A243184 A243185 * A243187 A243188 A243189

Keyword

nonn

Author

N. J. A. Sloane, Jun 05 2014

Status

approved