login
Squares that can be written as a sum of 3 distinct nonzero squares in no more than one way.
2

%I #7 Aug 11 2015 01:15:08

%S 49,81,121,169,196,289,324,484,676,784,1156,1296,1936,2704,3136,4624,

%T 5184,7744,10816,12544,18496,20736,30976,43264,50176,73984,82944,

%U 123904

%N Squares that can be written as a sum of 3 distinct nonzero squares in no more than one way.

%t 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 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 s1 = Join[{First[t]}, f1[t]]

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Feb 19 2012