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 A211507 #4 Apr 19 2012 17:39:11
%S A211507 0,0,0,1,2,3,4,3,9,9,4,17,11,7,18,16,19,21,16,21,35,24,8,35,42,17,44,
%T A211507 40,25,47,28,47,56,28,30,76,69,11,52,68,54,81,36,33,99,61,38,99,77,51,
%U A211507 76,88,63,67,92,88,140,40,12,153,90,71,98,121,98,104,100,41
%N A211507 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2=x*y-n.
%C A211507 For a guide to related sequences, see A211422.
%t A211507 t[n_] := t[n] = Flatten[Table[w^2 - x*y + n, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
%t A211507 c[n_] := Count[t[n], 0]
%t A211507 t = Table[c[n], {n, 0, 80}] (* A211507 *)
%Y A211507 Cf. A211422.
%K A211507 nonn
%O A211507 0,5
%A A211507 _Clark Kimberling_, Apr 14 2012