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 A083019 Number of common divisors of n and F(n) where F(n) denotes the n-th Fibonacci number. 1
 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 6, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 8, 3, 1, 1, 1, 1, 4, 1, 1, 1, 1, 2, 9, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 10, 1, 3, 1, 1, 1, 2, 2, 2, 1, 1, 1, 12, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 12, 1, 1, 3, 1, 1, 2, 1, 2, 1, 1, 1, 6, 2, 1, 1, 1, 1, 4, 2, 1, 1, 1, 2, 12, 1, 1, 1, 3, 1, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 MATHEMATICA Table[Length[Intersection[Divisors[n], Divisors[Fibonacci[n]]]], {n, 120}] (* Harvey P. Dale, Aug 24 2014 *) a[n_] := DivisorSigma[0, GCD[n, Fibonacci[n]]]; Array[a, 100] (* Amiram Eldar, Oct 18 2019 *) PROG (PARI) a(n) = length(setintersect(divisors(n), divisors(fibonacci(n)))); \\ Michel Marcus, Dec 04 2013 CROSSREFS Cf. A000045. Sequence in context: A236344 A333124 A274109 * A137865 A052494 A317756 Adjacent sequences:  A083016 A083017 A083018 * A083020 A083021 A083022 KEYWORD nonn,easy AUTHOR Benoit Cloitre, May 31 2003 STATUS approved

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Last modified September 19 17:46 EDT 2021. Contains 347564 sequences. (Running on oeis4.)