whamtet

(defn next-prime
  ([] (concat [2 3] (next-prime [2 3])))
  ([primes]
   (loop [candidate (-> primes peek (+ 2))]
     (if (->> primes
              (take-while #(<= % (Math/sqrt candidate)))
              (some #(zero? (mod candidate %))))
       (recur (+ candidate 2))
       (lazy-seq (cons candidate (next-prime (conj primes candidate))))))))