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A207638 Squares that can be written as a sum of 3 distinct nonzero squares in no more than one way. 2
49, 81, 121, 169, 196, 289, 324, 484, 676, 784, 1156, 1296, 1936, 2704, 3136, 4624, 5184, 7744, 10816, 12544, 18496, 20736, 30976, 43264, 50176, 73984, 82944, 123904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

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]]

CROSSREFS

Sequence in context: A294028 A056938 A267986 * A286095 A106311 A006832

Adjacent sequences:  A207635 A207636 A207637 * A207639 A207640 A207641

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Feb 19 2012

STATUS

approved

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Last modified October 15 21:06 EDT 2018. Contains 316237 sequences. (Running on oeis4.)