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A061305
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Squarefree Fibonacci numbers.
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6
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1, 1, 2, 3, 5, 13, 21, 34, 55, 89, 233, 377, 610, 987, 1597, 4181, 6765, 10946, 17711, 28657, 121393, 196418, 317811, 514229, 1346269, 2178309, 3524578, 5702887, 9227465, 24157817, 39088169, 63245986, 102334155, 165580141, 433494437, 701408733, 1134903170, 1836311903
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OFFSET
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1,3
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COMMENTS
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Union of A074691 and A075735. [From R. J. Mathar, Feb 06 2010]
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LINKS
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Zak Seidov, Table of n, a(n) for n = 1..200.
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FORMULA
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A000045 \ A061899. a(n) = A000045(A037918(n)). [From R. J. Mathar, Feb 16 2010]
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EXAMPLE
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55 = 5 * 11 is a squarefree Fibonacci number.
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MATHEMATICA
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Needs["NumberTheory`NumberTheoryFunctions`"]; a={}; Do[f=Fibonacci[n]; If[SquareFreeQ[f], AppendTo[a, f]], {n, 1, 30}]; a (Vladimir Orlovsky, Jul 22 2008)
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PROG
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(PARI) { n=0; g=0; f=1; for (i=1, 500, if (issquarefree(g), write("b061305.txt", n++, " ", g)); if (n==200, break); s=f; f+=g; g=s ) } [From Harry J. Smith, Jul 21 2009]
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CROSSREFS
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Cf. A000045.
Sequence in context: A145908 A173830 A224223 * A177374 A142881 A163159
Adjacent sequences: A061302 A061303 A061304 * A061306 A061307 A061308
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KEYWORD
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nonn,easy
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 26 2001
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EXTENSIONS
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More terms from Asher Natan Auel (auela(AT)reed.edu), May 14, 2001
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STATUS
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approved
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