A092574 Positive integers that can be represented in the form x^2 + 3y^2 with (x,y) = 1 and x and y positive.

4, 7, 12, 13, 19, 21, 28, 31, 37, 39, 43, 49, 52, 57, 61, 67, 73, 76, 79, 84, 91, 93, 97, 103, 109, 111, 124, 127, 129, 133, 139, 147, 148, 151, 156, 157, 163, 169, 172, 181, 183, 193, 196, 199, 201, 211, 217, 219, 223, 228, 229, 237, 241, 244, 247, 259, 268

Offset: 1

Author

Eric W. Weisstein, Feb 28 2004

Keywords

• nonn

Comments

Superset of primes of the form 6n+1 (A002476).

For all proper solutions with nonnegative x and y see A244819. - Wolfdieter Lang, Mar 02 2021

Links

• E. Akhtarkavan, M. F. M. Salleh and O. Sidek, Multiple Descriptions Video Coding Using Coinciding Lattice Vector Quantizer for H.264/AVC and Motion JPEG2000, World Applied Sciences Journal 21 (2): 157-169, 2013. - From _N. J. A. Sloane_, Feb 11 2013
• Eric Weisstein's World of Mathematics, Eulers 6n Plus 1 Theorem

Crossrefs

Cf. A002476, A092572, A092573, A092575, A244819.