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Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2>=n.
2

%I #5 Dec 04 2016 19:46:27

%S 0,1,8,27,63,124,215,339,508,725,993,1324,1718,2186,2733,3358,4079,

%T 4896,5812,6836,7974,9235,10616,12132,13789,15587,17538,19639,21904,

%U 24341,26946,29731,32708,35877,39238,42806,46581,50575,54794,59232

%N Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2>=n.

%C For a guide to related sequences, see A211422.

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

%t (Do[If[w^2 + x^2 + y^2 >= n, s = s + 1],

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

%t Map[t[#] &, Range[0, 80]] (* A211641 *)

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

%Y Cf. A211422.

%K nonn

%O 0,3

%A _Clark Kimberling_, Apr 18 2012