# [R] Fibonacci

Erich Neuwirth erich.neuwirth at univie.ac.at
Wed Apr 20 12:45:19 CEST 2011

```The "easy" solution to compute the Fibonacci numbers is

fibo <- function(n,a=1,b=1){
if (n == 1) return(a)
if (n == 2) return(b)
return(fibo(n-1,b,a+b))
}

It avoids double recursion.
It is, however, not as resource efficient as a loop since R does not do
tail recursion elimination.

On Apr 20, 2011, at 11:42 AM, Georgina Imberger wrote:

> Hi!
>
> I am trying to work out the code to get a Fibonacci sequence, using the
> while() loop and only one variable. And I can't figure it out.
>
> Fibonacci<-c(1,1)
> while (max(Fibonacci)<500){
> Fibonacci<-c(Fibonacci, (max(Fibonacci) + ?(Fibanacci)))
> }
>
>
> How can I tell R to take the value one before the max value? (Without
> defining another variable)
>
> (Probably super easy... I am a beginner...)
>
> Thanks,
> Georgie
>
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