A078183 Number of solutions to x^2 + y^2 + z^2 < n^2; number of lattice points inside a sphere of radius n.

0, 1, 27, 93, 251, 485, 895, 1365, 2103, 2969, 4139, 5497, 7123, 9093, 11459, 13997, 17071, 20377, 24303, 28545, 33371, 38641, 44395, 50733, 57747, 65117, 73447, 82201, 91911, 101769, 112931, 124289, 137059, 150165, 164415, 179309, 195167

Offset: 0

Author

T. D. Noe, Nov 21 2002

Keywords

• nonn

Crossrefs

Cf. A000605, A016725.

Programs

Mathematica

s = 0; Table[s = s + Sum[SquaresR[3, k], {k, (n - 1)^2, n^2 - 1}], {n, 0, 50}]

Formula

a(n) = A000605(n) - A016725(n)