OFFSET
0,7
COMMENTS
For a guide to related sequences, see A211422.
FORMULA
G.f.: (theta_3(x) - 1)^3/(8*(1 - x)), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Apr 17 2018
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w^2 + x^2 + y^2 <= n, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 80]] (* A211639 *)
(* Peter J. C. Moses, Apr 13 2012 *)
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Clark Kimberling, Apr 18 2012
STATUS
approved