OFFSET
1,3
COMMENTS
Also numbers representable as x^2 + 7*x*y + y^2 with 0 <= x <= y. - Gheorghe Coserea, Jul 29 2018
Also numbers of the form x^2 - x*y - 11*y^2 with 0 <= x <= y (or x^2 + x*y - 11*y^2 with x, y nonnegative). - Jianing Song, Jul 31 2018
Also nonnegative integers of the form 9x^2 - 5y^2. - Jon E. Schoenfield, Jun 03 2022
LINKS
Gheorghe Coserea, Table of n, a(n) for n = 1..100001
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 01 2014
STATUS
approved