A020685 Numbers of form 5 x^2 + 6 y^2.

0, 5, 6, 11, 20, 24, 26, 29, 44, 45, 51, 54, 59, 69, 74, 80, 86, 96, 99, 101, 104, 116, 125, 131, 134, 141, 149, 150, 155, 170, 176, 179, 180, 186, 195, 204, 216, 221, 230, 234, 236, 245, 251, 261, 269, 275, 276, 294, 296, 299, 314, 320, 326, 330, 339, 341, 344, 374, 384

Offset

1,2

Links

Harvey P. Dale, 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

Module[{upto=400}, Select[Union[Flatten[{5*First[#]^2+6*Last[#]^2, 6*First[#]^2+ 5*Last[#]^2}&/@Tuples[Range[0, Ceiling[Sqrt[ upto/5]]], 2]]], #<=upto&]] (* Harvey P. Dale, Sep 04 2013 *)

Crossrefs

Sequence in context: A236387 A344555 A039918 * A275492 A046828 A328095

Adjacent sequences: A020682 A020683 A020684 * A020686 A020687 A020688

Keyword

easy,nonn

Author

David W. Wilson

Status

approved