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A212102 Number of (w,x,y,z) with all terms in {1,...,n} and 1/w=1/x+1/y+1/z.

%I A212102 #12 Dec 28 2019 07:46:42
%S A212102 0,0,0,1,4,4,11,11,14,15,18,18,34,34,34,56,59,59,78,78,105,112,112,
%T A212102 112,143,143,143,144,177,177,235,235,238,245,245,269,318,318,318,319,
%U A212102 367,367,416,416,422,471,471,471,517,517,520,521,530,530,549,561
%N A212102 Number of (w,x,y,z) with all terms in {1,...,n} and 1/w=1/x+1/y+1/z.
%C A212102 For a guide to related sequences, see A211795.
%H A212102 Seiichi Manyama, <a href="/A212102/b212102.txt">Table of n, a(n) for n = 0..150</a>
%e A212102 a(4) counts these: (1,3,3,3), (1,2,4,4), (1,4,2,4), (1,4,4,2).
%t A212102 t = Compile[{{n, _Integer}}, Module[{s = 0},
%t A212102 (Do[If[w*(y*z + z*x + x*y) == x*y*z, s = s + 1],
%t A212102 {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
%t A212102 Map[t[#] &, Range[0, 60]] (* A212102 *)
%t A212102 (* _Peter J. C. Moses_, Apr 13 2012 *)
%Y A212102 Cf. A211795.
%K A212102 nonn
%O A212102 0,5
%A A212102 _Clark Kimberling_, May 03 2012