OFFSET
1,3
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)
MAPLE
select(t -> nops([isolve(x^2-61*y^2=t)])>0, [$0..200]); # Robert Israel, Jun 11 2014
PROG
(C++) // Computed using Will Jagy's C++ program Conway_Positive_All (see A243655 for the source code).
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 10 2014
STATUS
approved