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

%I #6 Dec 04 2016 19:46:27

%S 0,0,1,4,4,7,11,17,17,23,26,35,38,44,48,60,60,69,78,87,87,102,108,120,

%T 121,133,139,157,163,169,178,196,196,214,220,238,241,256,266,284,284,

%U 299,314,329,332,359,365,383,386,401,410,434,440,458,471,495

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

%C Is A211643 a subsequence of A211639?

%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 <= 2 n, s = s + 1],

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

%t Map[t[#] &, Range[0, 80]] (* A211643 *)

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

%Y Cf. A211422.

%K nonn

%O 0,4

%A _Clark Kimberling_, Apr 18 2012