let rec liste n m =
   if n>m then []
          else n::(liste (n+1) m);; 


let rec cribble_aux = function 
    []   -> []
  | t::r -> t::(cribble_aux 
                  (List.fold_right 
                     (function x -> 
                        function l -> 
                          if (x mod t) = 0 then l else (x::l)
                     ) 
                   r []) 
                );;
 
let cribble n = cribble_aux (liste 2 n);;