cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A211633 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2>2x^2+2y^2.

Original entry on oeis.org

0, 0, 0, 8, 32, 80, 160, 264, 416, 624, 864, 1176, 1552, 2000, 2528, 3144, 3856, 4640, 5552, 6584, 7712, 8960, 10352, 11880, 13520, 15328, 17296, 19416, 21712, 24176, 26832, 29640, 32672, 35904, 39312, 42968, 46816, 50896, 55184, 59736
Offset: 0

Views

Author

Clark Kimberling, Apr 17 2012

Keywords

Comments

For a guide to related sequences, see A211422.

Crossrefs

Cf. A211422.

Programs

  • Mathematica
    t = Compile[{{u, _Integer}},
       Module[{s = 0}, (Do[If[w^2 > 2 x^2 + 2 y^2,
             s = s + 1], {w, #}, {x, #}, {y, #}] &[
          Flatten[{Reverse[-#], #} &[Range[1, u]]]]; s)]];
    Map[t[#] &, Range[0, 50]]  (* A211633 *)
    %/8                        (* integers *)
    (* Peter J. C. Moses, Apr 13 2012 *)