As an exercise I implemented the mathematical power function. Once using recur:

(defn power [a n]
  (let [multiply (fn [x factor i]
                   (if (zero? i)
                     x
                     (recur (* x factor) factor (dec i))))]
  (multiply a a (dec n))))

And once with lazy-seq:

(defn power [a n]
  (letfn [(multiply [a factor]
            (lazy-seq
              (cons a (multiply (* a factor) factor))))]
  (nth (multiply a a) (dec n))))

Which implementation do you think is superior? I truly have no idea.. (I'd use recur because it's easier to understand.)

I read that lazy-seq is fast because is uses internal caching. But I don't see any opportunities for caching in my sample. Am I overlooking something?