A207639 Squares that can be written as a sum of 3 distinct nonzero squares in more than one way.

225, 361, 441, 529, 625, 729, 841, 900, 961, 1089, 1225, 1369, 1444, 1521, 1681, 1764, 1849, 2025, 2116, 2209, 2401, 2500, 2601, 2809, 2916, 3025, 3249, 3364, 3481, 3600, 3721, 3844, 3969, 4225, 4356, 4489, 4761, 4900, 5041, 5329, 5476, 5625, 5776, 5929

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Feb 19 2012

Keywords

• nonn

Programs

Mathematica

t = Sort[Select[Flatten[Table[x^2 + y^2 + z^2, {x, 400}, {y, x + 1, 400}, {z, y + 1, 400}]], # < 160006 && IntegerQ[Sqrt[#]] &]];
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];
s1 = Join[{First[t]}, f1[t]];
Complement[t, s1]