A212141 Number of (w,x,y,z) with all terms in {1,...,n} and w < (geometric mean of x,y,z).

0, 0, 7, 36, 111, 274, 567, 1056, 1789, 2859, 4350, 6370, 9000, 12387, 16642, 21906, 28326, 36064, 45273, 56151, 68884, 83685, 100758, 120316, 142530, 167745, 196141, 227976, 263553, 303172, 347031, 395529, 448912, 507534, 571680

Offset

0,3

Comments

A212141(n)+A212142(n)=n^4. For a guide to related sequences, see A211795.

Links

Table of n, a(n) for n=0..34.

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w^3 < x*y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212141 *)
(* Peter J. C. Moses, Apr 13 2012 *)

Crossrefs

Cf. A211795.

Sequence in context: A163683 A103090 A250414 * A212088 A184246 A097554

Adjacent sequences: A212138 A212139 A212140 * A212142 A212143 A212144

Keyword

nonn

Author

Clark Kimberling, May 06 2012

Status

approved