Just for fun, with a recursive definition of the Fibonacci function:

#!/usr/bin/perl

use strict;
use warnings;
use Memoize;
memoize 'fibo';

my $val = shift;
printf "%.12f\n", fibo($val+1)/fibo($val);

sub fibo {
    my $n = shift;
    return $n if ($n < 2);
    return fibo ($n-1) + fibo ($n-2);
}
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This gives the following result:

$ perl fibo3.pl 32
1.618033988750
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