I have an archive page that displays the number of articles published. Because there were so many, I ran a pagination script:

for 127.0.0.1/archive/2/?p=x&pp=y

where p is the page number and pp is number of articles to display per page.

The pagination looks like this:

Prev  1  2  3  4 ... 12   NEXT

with each item linking to p like <a href="?p=x">x</a>.

I also have the items per page setter: 25 | 50 | 100 (<a href="?pp=y">y</a>).

Now I have a PHP script that fixes pp into a session variable. But I am worried about duplicate content (since incrementing pp values will be inclusive) and also content not getting indexed because its not in the pagination link. so in the example above, pages 5-11 will not be indexed.

Any ideas on how to fix this?