A272331 Refactorable Fibonacci numbers.

1, 2, 8, 46368, 4807526976

Offset

1,2

Comments

Luca & Young prove that there are no more terms in this sequence. - Charles R Greathouse IV, Apr 27 2016

Links

Table of n, a(n) for n=1..5.

Florian Luca and Paul Thomas Young, On the number of divisors of n! and of the Fibonacci numbers

Formula

a(n) = A000045(A160683(n+1)). - Michel Marcus, Apr 25 2016

Example

8 is a term as a Fibonacci number that is divisible by the number of its divisors, (1,2,4,8), which is 4.

Maple

select(t -> t mod numtheory:-tau(t) = 0, map(combinat:-fibonacci, [$2..200])); # Robert Israel, Apr 27 2016

Mathematica

DeleteDuplicates@Select[Fibonacci@Range@200, Divisible[#, IntegerLength@#]&]

Prog

(PARI) for(n=2, 200, fn=fibonacci(n); fn%numdiv(fn)==0&&print1(fn ", "))

Crossrefs

Intersection of A000045 (Fibonacci numbers) and A033950 (refactorable numbers).

Cf. A000005 (number of divisors), A160683.

Sequence in context: A185681 A046967 A007753 * A256065 A081979 A012672

Adjacent sequences: A272328 A272329 A272330 * A272332 A272333 A272334

Keyword

nonn,fini,full

Author

Waldemar Puszkarz, Apr 25 2016

Status

approved