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A037918
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Numbers n such that the Fibonacci number F(n) is squarefree.
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15
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1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 49, 51, 52, 53, 55, 57, 58, 59, 61, 62, 63, 64, 65, 67, 68, 69, 70, 71, 73, 74, 76, 77, 79, 80, 81, 82, 83, 85, 86, 87, 88, 89, 92
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OFFSET
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1,2
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LINKS
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EXAMPLE
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10 is in the sequence because F(10) = 55, which is squarefree since 55 = 5 * 11.
11 is in the sequence because F(11) = 89, which is prime and therefore also squarefree.
12 is not in the sequence because F(12) = 144 = 2^4 * 3^2 = 12^2.
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MATHEMATICA
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Select[Range[100], MoebiusMu[Fibonacci[#]] != 0 &] (* Alonso del Arte, Jan 26 2014 *)
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PROG
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(PARI) select(n->(0!=moebius(fibonacci(n))), vector(100, j, j)) \\ Joerg Arndt, Jan 28 2014
(Magma) [n: n in [1..100] | IsSquarefree(Fibonacci(n))]; // Vincenzo Librandi, Jun 01 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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