OFFSET
0,5
COMMENTS
For a guide to related sequences, see A211795.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..150
EXAMPLE
a(4) counts these: (1,3,3,3), (1,2,4,4), (1,4,2,4), (1,4,4,2).
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w*(y*z + z*x + x*y) == x*y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 60]] (* A212102 *)
(* Peter J. C. Moses, Apr 13 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 03 2012
STATUS
approved