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A179334
Squares that are the sum of three positive Fibonacci numbers.
1
4, 9, 16, 25, 36, 49, 64, 81, 100, 144, 256, 289, 324, 400, 529, 576, 625, 1024, 1089, 1225, 1369, 1600, 2209, 3249, 7396, 12544, 15129, 19321, 46656, 103684, 710649, 1347921, 2178576, 4870849, 14930496, 24990001, 33385284, 228826129, 1568397609, 10749957124
OFFSET
1,1
EXAMPLE
a(5) = 36 = 1+1+34 = Fib(1)+Fib(2)+Fib(9).
MATHEMATICA
f=Fibonacci[Range[40]]; Select[Union[Flatten[Outer[Plus, f, f, f]]], #<f[[-1]]+2 && IntegerQ[Sqrt[#]] &]
Select[Union[Total/@Tuples[Fibonacci[Range[50]], 3]], IntegerQ[Sqrt[ #]]&] (* Harvey P. Dale, Apr 29 2015 *)
CROSSREFS
Cf. A000045.
Sequence in context: A030476 A077355 A077487 * A068867 A068864 A068854
KEYWORD
nonn
AUTHOR
Carmine Suriano, Jan 12 2011
STATUS
approved