A212062 Number of (w,x,y,z) with all terms in {1,...,n} and w^2 = x*y*z.

0, 1, 4, 7, 16, 19, 31, 34, 50, 68, 80, 83, 122, 125, 137, 149, 185, 188, 233, 236, 269, 281, 293, 296, 368, 410, 422, 456, 489, 492, 570, 573, 630, 642, 654, 666, 792, 795, 807, 819, 891, 894, 954, 957, 990, 1047, 1059, 1062, 1191, 1269, 1350

Offset: 0

Author

Clark Kimberling, Apr 30 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A211795.

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A211795.

Programs

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]] (* A212062 *)
(* Peter J. C. Moses, Apr 13 2012 *)