(use '[clojure.contrib.lazy-seqs :only [primes]])
(defn lpf [n]
[n (or (last
(for [p (take-while #(<= (* % %) n) primes)
:when (zero? (rem n p))]
p))
1)])
(->> (range 2 100000)
(pmap lpf)
(apply max-key second)
println
time)