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 A211430 #4 Apr 15 2012 21:22:45
%S A211430 1,7,15,25,35,49,63,77,93,111,129,147,165,187,209,231,253,275,299,325,
%T A211430 351,377,403,429,455,485,515,545,575,605,635,665,697,731,765,799,833,
%U A211430 867,901,935,969,1007,1045,1083,1121,1159,1197,1235,1273,1311
%N A211430 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2+x+y=0.
%C A211430 For a guide to related sequences, see A211422.
%t A211430 t[n_] := t[n] = Flatten[Table[w^2 + x + y, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
%t A211430 c[n_] := Count[t[n], 0]
%t A211430 t = Table[c[n], {n, 0, 70}] (* A211430 *)
%t A211430 (t - 1)/2 (* integers *)
%Y A211430 Cf. A211422.
%K A211430 nonn
%O A211430 0,2
%A A211430 _Clark Kimberling_, Apr 10 2012