OFFSET
1,5
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
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
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, May 31 2003
STATUS
approved