excluding more than one category from random post

I found a couple of random post plugins for the sidebar but they all call for using widgets and come with their own styling that seems like too much work to customize.

I decided to use the coding recommended in the codex: https://codex.www.ads-software.com/Template_Tags/get_posts#Random_posts

But I had a little difficulty figuring out how to exclude more than one category. After googling, I came across the following page
https://blog.websitestyle.com/index.php/2006/11/02/wordpress-how-to-exclude-categories-from-a-feed/ to finally come up with this:

$args = array( 'posts_per_page' => 5, 'orderby' => 'rand', 'category' => -4, 'category' => -7, 'category' => -13 );

It works, but there must be a shorter way to exclude more than one category! Please advise.

Thank you.

E Morris

This is the full coding I have right now:

<!-- start random post links -->
<li><strong><?php _e('5 randomly chosen posts:'); ?></strong></li>
<?php
$args = array( 'posts_per_page' => 5, 'orderby' => 'rand', 'category' => -4, 'category' => -7, 'category' => -13 );
$rand_posts = get_posts( $args );
foreach( $rand_posts as $post ) : ?>
	<li><a href="<?php the_permalink(); ?>"  title="<?php the_title(); ?>"><?php the_title(); ?></a></li>
<?php endforeach; ?>
<!-- end random post links -->