let rec
   to = lambda n.
      let rec up = lambda m.
         if m=n+1 then nil
         else m :: up (m+1)
      in up 1

in let rec
   filter = lambda f. lambda l.
      if null l then nil
      else if hd l/f*f = hd l then filter f  tl l
      else hd l :: filter f  tl l,

   sieve = lambda l.
      if null l then nil
      else hd l :: sieve (filter  hd l  tl l)

in sieve tl(to 50)