A211432 - OEIS

%I #4 Apr 16 2012 16:21:00

%S 1,9,17,25,33,57,65,73,81,89,113,121,129,153,161,185,193,217,225,233,

%T 257,265,273,281,289,329,353,361,369,393,417,425,433,441,465,489,497,

%U 521,529,553,577,601,609,617,625,649,657,665,673,681,721,745

%N Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2=x^2+y^2.

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

%t t[n_] := t[n] = Flatten[Table[-w^2 + x^2 + y^2, {w, -n, n}, {x, -n, n}, {y, -n, n}]]

%t c[n_] := Count[t[n], 0]

%t t = Table[c[n], {n, 0, 70}]  (* A211432 *)

%t (t - 1)/8                    (* integers *)

%Y Cf. A211422.

%K nonn

%O 0,2

%A _Clark Kimberling_, Apr 10 2012