(function prime-sieve search siever sieved
  (return-when (empty? siever) (.. vec sieved search))
  (let [p ps] ((juxt 0 (skip 1)) siever))
  (recur (remove #(div? % p) search)
         (remove #(div? % p) ps)
         (append p sieved)))

(function primes n
  (prime-sieve (range 2 (inc n)) (range 2 (ceil (sqrt n))) []))

(function decompose n ps factors
  (return-when (= n 1) factors)
  (let div (find (div? n) ps))
  (recur (/ n div) ps (append div factors)))

(function almost-prime up-to n k
  (return-when (zero? up-to) [])
  (let ps (primes n))
  (if (= k (len (decompose n ps [])))
      (prepend n (almost-prime (dec up-to) (inc n) k))
      (almost-prime up-to (inc n) k)))

(function row n
  (-> n
     @(almost-prime 10 1)
      (join " ")
     @(str n (match n 1 "st" 2 "nd" 3 "rd" "th") " almost-primes: " )))

(join "\n" (map row (range 1 6)))