Re: Fibonacci[1,000,000,000] contains 208,987,640 decimal digits

From: Klueless (klueless_at_worldnet.att.net)
Date: 08/09/04 

Date: Mon, 09 Aug 2004 16:07:36 GMT

"Michael Taktikos" <michael.taktikos@hanse.net> wrote in message news:2npfirF385mqU1@uni-berlin.de...
> "Ed Pegg Jr" <edpegg@gmail.com> wrote in comp.soft-sys.math.mathematica:
> > For finding the number of digits in any sufficently large Fibonacci
> > number in base 10, let k = (ArcCsch[2])/Log[10]. The number of
> > digits in Fibonacci[n] is Round[n k].

      That formula may be wrong 15.05149978...% of the time.
This formula:

     Round[(ArcCsch[2]*n+Log[2]/2)/Log[10]] (n>=2)

should be more reliable, but may be still not perfect.