A014203 Sum {i^2+j^2+k^2}, i^2+j^2+k^2 <= n.

0, 6, 30, 54, 78, 198, 342, 342, 438, 708, 948, 1212, 1308, 1620, 2292, 2292, 2388, 3204, 3852, 4308, 4788, 5796, 6324, 6324, 6900, 7650, 9522, 10386, 10386, 12474, 13914, 13914, 14298, 15882, 17514, 19194, 20274, 21162, 23898, 23898, 24858

Offset

0,2

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 107.

Links

Table of n, a(n) for n=0..40.

Example

Take n=3 say. The sum contains the terms 0 (once) from (0,0,0); 1 (6 times) from (+-1,0,0); 2 (12 times) from (+-1, +-1, 0); and 3 (8 times) from (+-1, +-1, +-1); for a total of 0+6+24+24=54.

Crossrefs

Sequence in context: A110175 A249676 A259752 * A044083 A239978 A024406

Adjacent sequences: A014200 A014201 A014202 * A014204 A014205 A014206

Keyword

nonn

Author

E.V. Flynn (evflynn(AT)liverpool.ac.uk)

Extensions

More terms from James A. Sellers, Feb 05 2000

Status

approved