From One End to the Other (Elm)

from_one_end_to_the_other.elm

import Graphics.Element exposing (show)
import Array exposing (..)
import String exposing (..)

magicNumber : Array Int
magicNumber =
  let
    isNumber number =  
      String.right 1 (toString(number)) == "6" &&
      (String.append "6" (String.dropRight 1 (toString(number))))
        == toString(number * 4)
        
  in
    Array.filter isNumber (initialize 100000 (\n -> n * 2))
  
main = show magicNumber
-- Array.fromList [153846]