(defn sieve [potentials primes]    ; stackoverflow.com/q/2946764/849891
  (if-let [p (first potentials)]
      (if (> (* p p) (last potentials))
        (concat primes potentials)
        (recur (filter (fn [n] (not= (mod n p) 0)) potentials)
               (conj primes p)))
    primes))
 
(print ( (fn [s] [(count s),(last s)]) (sieve (range 2 160000) []))) 
 
; (print  (sieve (range 2 128) []))  
 
; 30th prime: 113^2=12769  31st prime: 127^2=16129   1862nd prime: 15991
 
; 14,683rd: 159979   below 160,000   --  1.17s (w/ doall: 1.23s)
 
;  (just 78 primes below 400)

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