%I #13 Jun 25 2020 15:14:07

%S 1,5,9,21,25,29,49,53,57,69,73,77,105,109,113,125,137,141,161,165,169,

%T 181,185,189,217,229,233,261,265,269,297,301,313,325,329,333,369,373,

%U 377,389,393,397,417,421,425,445,449,453,497,517,529,541,545

%N Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2+3*x*y=0.

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

%H Brandon Crofts, <a href="/A211424/b211424.txt">Table of n, a(n) for n = 0..20000</a>

%H Brandon Crofts, <a href="/A211424/a211424.txt">Faster Mathematica code for A211424</a>

%t t[n_] := t[n] = Flatten[Table[w^2 + 3 x*y, {w, -n, n}, {x, -n, n}, {y, -n, n}]]

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

%t t = Table[c[n], {n, 0, 70}] (* A211424 *)

%t (t - 1)/4 (* integers *)

%Y Cf. A211422.

%K nonn

%O 0,2

%A _Clark Kimberling_, Apr 10 2012