A207640 - OEIS

A207640

Squares that can be written as a sum of 3 distinct nonzero squares in exactly two ways.

225, 361, 625, 900, 1444, 2500, 3600, 5776, 10000, 14400, 23104, 40000, 57600, 92416

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OFFSET

1,1

LINKS

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];

f2[l_] := Module[{t = {}}, Do[If[l[[n]] == l[[n + 1]], AppendTo[t, l[[n]]]], {n, Length[l] - 1}]; t];

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

Complement[t, s1];

t = f2[t];

s2 = Join[{First[t]}, f1[t]]

CROSSREFS

KEYWORD

nonn

AUTHOR

STATUS

approved