OFFSET
1,3
COMMENTS
Discriminant 53.
Same as nonnegative integers represented by the form x^2 - 53*y^2 (or 53*x^2 - y^2). - Robert Israel, Jun 11 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)
MAPLE
select(t -> nops([isolve(x^2-53*y^2=t)])>0, [$0..1000]); # Robert Israel, Jun 11 2014
MATHEMATICA
Reap[For[n = 0, n <= 30, n++, If[Reduce[1*x^2 + 7*x*y - 1*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]]
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 06 2014
EXTENSIONS
More terms from Colin Barker, Jun 10 2014
STATUS
approved