A212063 Number of (w,x,y,z) with all terms in {1,...,n} and w^2<x*y*z.

0, 0, 8, 50, 169, 440, 943, 1796, 3118, 5090, 7877, 11683, 16708, 23253, 31552, 41892, 54589, 70030, 88524, 110484, 136289, 166434, 201327, 241465, 287278, 339444, 398407, 464742, 539068, 622021, 714192, 816319, 929007, 1053100

Offset

0,3

Comments

a(n)+A212064(n)=n^4. For a guide to related sequences, see A211795.

Links

Table of n, a(n) for n=0..33.

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w^2 < x*y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212063 *)
(* Peter J. C. Moses, Apr 13 2012 *)

Crossrefs

Cf. A211795.

Sequence in context: A301487 A299686 A133426 * A300318 A290617 A163228

Adjacent sequences: A212060 A212061 A212062 * A212064 A212065 A212066

Keyword

nonn

Author

Clark Kimberling, Apr 30 2012

Status

approved