'category__in' problems

$args = array(
        'category__in' => 13,22,23,30,45, //An array of category IDs to be included.
        'post__not_in' => array($post->ID), //An array of post IDs to be excluded from the results.
        'orderby'=> 'rand', //Lists Related posts Randomly. *** MODIFY IF YOU LIKE ***
        'showposts' => 10, //*** MODIFY TO WHAT YOU LIKE.***  Number of related posts to show.
        //'caller_get_posts' => 1 //*** USE THIS IF YOU ARE RUNNING WordPress Version < 3.1 ***
        'ignore_sticky_posts' => 1 //*** USE THIS for WordPress Version >= 3.1 ***
    );

I have this code but the category_in does not work, it only displays ID 13.

What is the correct way to get it to display all 5 categories? I tried putting the digits in brackets but my site got an error.