A212049 - OEIS

%I #5 Dec 04 2016 19:46:29

%S 0,0,0,0,0,18,26,30,38,44,108,116,144,152,172,280,314,326,372,384,564,

%T 612,652,668,752,954,1002,1056,1136,1156,1528,1552,1642,1718,1778,

%U 2084,2250,2278,2346,2430,2922,2954,3150,3182,3318,3830,3918,3954

%N Number of (w,x,y,z) with all terms in {1,...,n} and w*x=5*y*z.

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

%t t = Compile[{{n, _Integer}}, Module[{s = 0},

%t (Do[If[w*x == 5 y*z, s = s + 1],

%t {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];

%t Map[t[#] &, Range[0, 50]] (* A212049 *)

%t %/2  (* integers *)

%t (* _Peter J. C. Moses_, Apr 13 2012 *)

%Y Cf. A211795.

%K nonn

%O 0,6

%A _Clark Kimberling_, Apr 29 2012