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 A207638 #7 Aug 11 2015 01:15:08
%S A207638 49,81,121,169,196,289,324,484,676,784,1156,1296,1936,2704,3136,4624,
%T A207638 5184,7744,10816,12544,18496,20736,30976,43264,50176,73984,82944,
%U A207638 123904
%N A207638 Squares that can be written as a sum of 3 distinct nonzero squares in no more than one way.
%t A207638 t = Sort[Select[Flatten[Table[x^2 + y^2 + z^2, {x, 400}, {y, x + 1, 400}, {z, y + 1, 400}]], # < 160006 && IntegerQ[Sqrt[#]] &]];
%t A207638 f1[l_] := Module[{t = {}}, Do[If[l[[n]] != l[[n + 1]] && l[[n]] != l[[n - 1]], AppendTo[t, l[[n]]]], {n, Length[l] - 1}]; t];
%t A207638 s1 = Join[{First[t]}, f1[t]]
%K A207638 nonn
%O A207638 1,1
%A A207638 _Vladimir Joseph Stephan Orlovsky_, Feb 19 2012