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A207639 Squares that can be written as a sum of 3 distinct non-zero squares in more than one way. 2
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 (list; graph; refs; listen; history; text; internal format)
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: A247885 A044871 A202005 * A077347 A207640 A216419

Adjacent sequences:  A207636 A207637 A207638 * A207640 A207641 A207642

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Feb 19 2012

STATUS

approved

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Last modified December 21 12:18 EST 2014. Contains 252320 sequences.