A211632 Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and 2w^2>x^2+y^2.

0, 0, 24, 88, 224, 448, 776, 1224, 1840, 2640, 3624, 4840, 6304, 8016, 10008, 12328, 14976, 17952, 21336, 25112, 29296, 33920, 39016, 44568, 50640, 57264, 64440, 72168, 80496, 89456, 99032, 109256, 120208, 131840, 144168, 157288

Offset

0,3

Comments

For a guide to related sequences, see A211422.

Links

Table of n, a(n) for n=0..35.

Mathematica

t = Compile[{{u, _Integer}},
   Module[{s = 0}, (Do[If[2 w^2 > x^2 + y^2,
         s = s + 1], {w, #}, {x, #}, {y, #}] &[
      Flatten[{Reverse[-#], #} &[Range[1, u]]]]; s)]];
Map[t[#] &, Range[0, 50]]  (* A211632 *)
%/8                        (* integers *)

Crossrefs

Cf. A211422.

Sequence in context: A304375 A044211 A044592 * A305888 A233644 A010012

Adjacent sequences: A211629 A211630 A211631 * A211633 A211634 A211635

Keyword

nonn

Author

Clark Kimberling, Apr 17 2012

Status

approved