A211636 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2>=x^2+y^2.

0, 0, 1, 5, 13, 28, 50, 80, 121, 175, 244, 327, 425, 544, 683, 845, 1028, 1236, 1470, 1733, 2027, 2349, 2706, 3096, 3520, 3985, 4489, 5034, 5619, 6247, 6922, 7641, 8411, 9230, 10102, 11030, 12007, 13043, 14133, 15288, 16504, 17778, 19117

Offset

0,4

Comments

For a guide to related sequences, see A211422.

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
    (Do[If[w^2 >= x^2 + y^2, s = s + 1],
        {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]]    (* A211636 *)
(* Peter J. C. Moses, Apr 13 2012 *)

Prog

(PARI) a(n) = sum(j=0, n, sum(k=1, j-1, sqrtint(j^2-k^2))); \\ Seiichi Manyama, Oct 28 2023

Crossrefs

Cf. A211422, A211651.

Sequence in context: A344521 A316537 A175254 * A294172 A055328 A027962

Adjacent sequences: A211633 A211634 A211635 * A211637 A211638 A211639

Keyword

nonn

Author

Clark Kimberling, Apr 18 2012

Status

approved