Element, 20
=


    _'[1+2:'.2:`\ ."\
    `]

The main idea is that the stacks contain a string and a number. We repeatedly increment the number and append it to the string, printing the result.  Given that Element has zero support for arrays, I think this is a very decent score.

Since most people are probably unfamiliar with this language, Element is a golfing language I created in 2012.  You can see the most updated interpreter, written in Perl, [here](https://github.com/PhiNotPi/Element).

To make the explanation easier, I'll replace the newline with an `L`.

    _'[1+2:'.2:`\ ."\L`]
    _'                    input a number and put it onto the control stack
      [                ]  this is a FOR loop
       1+                 increment the number.  An empty stack is zero.
         2:               make a second copy of it
           '              put one copy on the control stack to save it
            .             append the other copy to the end of the string
             2:           make two copies of the new string
               `          output one of them
                \ .       append a space to the other
                   "      put the number from earlier pack onto the main stack
                    \L`   output a newline, but the L should be an actual newline