A207638 Squares that can be written as a sum of 3 distinct nonzero squares in no more than one way.

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

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: A056938 A267986 A337759 * A286095 A106311 A006832

Adjacent sequences: A207635 A207636 A207637 * A207639 A207640 A207641

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Feb 19 2012

Status

approved