(*
It can be seen that the number, 125874, and its double, 251748, contain exactly the same digits, but in a different order.

Find the smallest positive integer, x, such that 2x, 3x, 4x, 5x, and 6x, contain the same digits.
*)

let rec list_of_dec i =
  if(i=0) then [] else
  (i mod 10)::(list_of_dec (i/10))
;;

let compare l x =
  let lx = Sort.list (<) (list_of_dec x) in
  ( List.length l = List.length lx )&&
  ( List.for_all2 (=) l lx )

let rec search i =
  Printf.printf "%d\n" i;
  if(
    let l2i = (Sort.list (<) ( list_of_dec (2*i) )) in
    compare l2i (3*i) &&
    compare l2i (4*i) &&
    compare l2i (5*i) &&
    compare l2i (6*i) )
  then Printf.printf "found %d %d %d %d %d %d\n" i (i*2) (i*3) (i*4) (i*5) (i*6)
  else search (i+1)
;;

search 1;;