A020684 Numbers of form 4 x^2 + 9 y^2.

0, 4, 9, 13, 16, 25, 36, 40, 45, 52, 64, 72, 73, 81, 85, 97, 100, 109, 117, 136, 144, 145, 148, 153, 160, 180, 181, 196, 205, 208, 225, 229, 232, 241, 244, 256, 261, 265, 277, 288, 289, 292, 324, 325, 328, 333, 337, 340, 360, 369, 388, 400, 405, 409, 421, 424, 436, 441

Offset: 1

Author

David W. Wilson

Keywords

• easy
• nonn

Links

• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)