This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A211513 #4 Apr 21 2012 12:13:24
%S A211513 0,0,2,2,4,4,6,6,10,14,16,16,18,18,20,20,24,24,32,32,34,34,36,36,40,
%T A211513 46,48,52,54,54,56,56,66,66,68,68,76,76,78,78,82,82,84,84,86,90,92,92,
%U A211513 96,104,118,118,120,120,128,128,132,132,134,134,136,136,138,142
%N A211513 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2*w^2=x*y.
%C A211513 For a guide to related sequences, see A211422.
%t A211513 t[n_] := t[n] = Flatten[Table[2 w^2 - x*y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
%t A211513 c[n_] := Count[t[n], 0]
%t A211513 t = Table[c[n], {n, 0, 70}] (* A211513 *)
%t A211513 t/2 (* integers *)
%Y A211513 Cf. A211422.
%K A211513 nonn
%O A211513 0,3
%A A211513 _Clark Kimberling_, Apr 14 2012