You could use wp_paginate_links(), pass it the 'type' => 'array' parameter in the argument array, and then array_reverse() the output.
But: if you’re doing this for SEO purposes, don’t bother. Your canonical URL should be your single-post view, not an archive index; so the index archive page numbers should have minimal SEO impact, no matter what order the page numbering.
EDIT
wp_paginate_links() Codex ref
EDIT 2
If you want to reverse the order of the posts themselves, you’ll either need to use a custom query, or modify the default Loop query, likely by changing the $order from DESC to ASC.
EDIT 3
If you just want to reverse the order of the posts themselves, then just change $order from DESC to ASC, and don’t do an array_reverse() on the wp_paginate_links() call.