A212048 Number of (w,x,y,z) with all terms in {1,...,n} and 3w*x=4*y*z.

0, 0, 0, 2, 14, 18, 30, 34, 74, 104, 128, 136, 216, 228, 260, 318, 438, 454, 554, 570, 718, 812, 868, 888, 1128, 1182, 1250, 1398, 1614, 1642, 1864, 1892, 2204, 2354, 2446, 2570, 2990, 3026, 3126, 3304, 3760, 3800, 4128, 4168, 4520, 4906, 5030

Offset: 0

Author

Clark Kimberling, Apr 29 2012

Keywords

• nonn

Comments

Each term is divisible by 2. See A211795 for a guide to related sequences.

Crossrefs

Cf. A211795.

Programs

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
 (Do[If[3 w*x == 4 y*z, s = s + 1],
 {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212048 *)
%/2  (* integers *)
(* Peter J. C. Moses, Apr 13 2012 *)