With zeal Post Permalink you can specify direct links to posts of the type domain.com/post/number or domain.com/?post=number. The plugin expose one template functions:
za_post_permalink($id = 0)
The accepts a post ID and return the unique post permalink if the post exists, false otherwise. If 0 or nothing is passed than the function takes the current post (if any) and generate the permalink for that particular post.