This is designed to show 10 posts on each of the pages after the home/blog page when the home page only shows 5 (because if you just use posts_per_page=10 without the offset you will lose the most recent posts numbered 6-10 in between the first and secon home/blog paged).

You can tweak it to different numbers, but you'll need to change the maths (10 * ($page - 1) - 5) to suit.