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 A211511 #4 Apr 20 2012 15:06:50
%S A211511 0,0,2,2,4,4,6,6,10,12,14,14,18,18,20,20,24,24,30,30,32,32,34,34,40,
%T A211511 44,46,48,50,50,54,54,62,62,64,64,72,72,74,74,80,80,82,82,84,86,88,88,
%U A211511 94,100,110,110,112,112,118,118,124,124,126,126,132,132,134,136
%N A211511 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2=2x*y.
%C A211511 For a guide to related sequences, see A211422.
%t A211511 t[n_] := t[n] = Flatten[Table[w^2 - 2 x*y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
%t A211511 c[n_] := Count[t[n], 0]
%t A211511 t = Table[c[n], {n, 0, 60}] (* A211511 *)
%t A211511 t/2 (* integers *)
%Y A211511 Cf. A211422.
%K A211511 nonn
%O A211511 0,3
%A A211511 _Clark Kimberling_, Apr 14 2012