How to build a random generator without repetition

Hi there,

I want to build a random generator that does not have any repetition which I know I can use [urn] or [urn-jb] objects but my problem is, if I use these objects and set the random range as 5 for example, it is easy to predict the fourth and fifth random numbers because 3 numbers have been taken out.

So I want to have each number to be produced two times and there is not any repetition, but besides, it's not that easy to predict the left ones. Though I know there is no way to avoid prediction in this way but when the range is bigger the prediction will become harder.

I am attaching a patch that I could manage to build so far but unfortunately I still couldn't get rid of repetition.

<pre><code></code></pre>