I'm trying to write a bash shell script for a recursive Fibonacci sequence. What am I doing wrong?

#!/bin/bash function Fibonacci() { num=$num if (( $num <= 1)) then echo 1 else num=$(( $(Fibonacci $((num-1)) ) + $(Fibonacci $((num-2)) ) )) fi return $num } echo F($1) = $(Fibonacci $1)

It needs to allow reading in from the command line " ./filename {1...5} " and get an output that looks like

F(1) = 1

F(2) = 1

F(3) = 2 and so on