; For a pair of (assumed) consecutive (assumed) Fibonacci numbers and generates the next pair
(defn fib-pair [[a b]] ; I *think* this a vector and not just two parameters so that we can iterate (because you can't return two values)
    [b (+ a b)])

(print (fib-pair [3 5]))

(print 
    (take 5
        (map first (iterate fib-pair [1 1]))))

(print 
    (nth 
        (map first (iterate fib-pair [1 1]))
        50)) ;The book says 500th, but even 100th gives java.lang.ArithmeticException: integer overflow!