OFFSET
1,3
COMMENTS
Discriminant -60.
Norms of numbers in Z[sqrt(-15)]. - Alonso del Arte, Sep 23 2014
LINKS
Bruno Berselli, Table of n, a(n) for n = 1..1000
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
MATHEMATICA
nn = 22; Union[Select[Flatten[Table[x^2 + 15 y^2, {x, 0, nn}, {y, 0, nn}]], # <= nn^2 &]] (* Bruno Berselli, Jun 02 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 01 2014
STATUS
approved