A243187 Nonnegative integers of the form -x^2 + 6xy + 5y^2.

0, 5, 7, 10, 13, 14, 20, 26, 28, 31, 40, 45, 47, 52, 55, 56, 61, 62, 63, 77, 80, 90, 94, 101, 103, 104, 110, 112, 117, 122, 124, 125, 126, 143, 154, 157, 160, 167, 173, 175, 180, 181, 188, 199, 202, 206, 208, 215, 220, 223, 224, 229, 234, 244, 245, 248, 250, 252, 269, 271, 279, 286, 293

Offset

1,2

Comments

Discriminant 56.

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

Links

Table of n, a(n) for n=1..63.

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

Mathematica

Reap[For[n = 0, n <= 300, n++, If[Reduce[-1*x^2 + 6*x*y + 5*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]]

Crossrefs

Primes: A141191.

Sequence in context: A172321 A154689 A175766 * A333308 A179196 A024325

Adjacent sequences: A243184 A243185 A243186 * A243188 A243189 A243190

Keyword

nonn

Author

N. J. A. Sloane, Jun 05 2014

Status

approved