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A196266 Positive integers a for which there is a (-1/4)-Pythagorean triple (a,b,c) satisfying a<=b.

%I A196266 #8 Mar 30 2012 18:57:49
%S A196266 1,2,3,4,4,5,6,6,7,8,8,9,9,10,10,10,11,11,12,12,12,12,13,13,14,14,15,
%T A196266 15,16,16,17,17,18,18,18,19,19,20,20,20,20,20,20,21,22,22,22,23,23,23,
%U A196266 24,24,24,24,25,25,26,26,26,27,28,28,28,28,28,29,29,30,30,30,30
%N A196266 Positive integers a for which there is a (-1/4)-Pythagorean triple (a,b,c) satisfying a<=b.
%C A196266 See A195770 for definitions of k-Pythagorean triple, primitive k-Pythagorean triple, and lists of related sequences.
%t A196266 k = -1/4; c[a_, b_] := Sqrt[a^2 + b^2 + k*a*b];
%t A196266 d[a_, b_] := If[IntegerQ[c[a, b]], {a, b, c[a, b]}, 0]
%t A196266 t[a_] := Table[d[a, b], {b, a, z8}]
%t A196266 u[n_] := Delete[t[n], Position[t[n], 0]]
%t A196266 Table[u[n], {n, 1, 15}]
%t A196266 t = Table[u[n], {n, 1, z8}];
%t A196266 Flatten[Position[t, {}]]
%t A196266 u = Flatten[Delete[t, Position[t, {}]]];
%t A196266 x[n_] := u[[3 n - 2]];
%t A196266 Table[x[n], {n, 1, z7}]  (* A196266 *)
%t A196266 y[n_] := u[[3 n - 1]];
%t A196266 Table[y[n], {n, 1, z7}]  (* A196267 *)
%t A196266 z[n_] := u[[3 n]];
%t A196266 Table[z[n], {n, 1, z7}]  (* A196268 *)
%t A196266 x1[n_] := If[GCD[x[n], y[n], z[n]] == 1, x[n], 0]
%t A196266 y1[n_] := If[GCD[x[n], y[n], z[n]] == 1, y[n], 0]
%t A196266 z1[n_] := If[GCD[x[n], y[n], z[n]] == 1, z[n], 0]
%t A196266 f = Table[x1[n], {n, 1, z9}];
%t A196266 x2 = Delete[f, Position[f, 0]]  (* A196269 *)
%t A196266 g = Table[y1[n], {n, 1, z9}];
%t A196266 y2 = Delete[g, Position[g, 0]]  (* A196270 *)
%t A196266 h = Table[z1[n], {n, 1, z9}];
%t A196266 z2 = Delete[h, Position[h, 0]]  (* A196271 *)
%Y A196266 Cf. A195770, A196267, A196268, A196269.
%K A196266 nonn
%O A196266 1,2
%A A196266 _Clark Kimberling_, Sep 30 2011