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

1,1

Links

Table of n, a(n) for n=1..44.

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]

Crossrefs

Sequence in context: A044871 A202005 A359598 * A077347 A207640 A267892

Adjacent sequences: A207636 A207637 A207638 * A207640 A207641 A207642

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Feb 19 2012

Status

approved