The new site needs some work (details inside)

Support Blender Artists Website Support
3

vBulletin_posts_per_page = 10 (example)

page_3 = vBulletin_posts_per_page * 3

Append /30 to the thread url.

blenderartists.org/t/some_thread_title/thread_index

becomes

blenderartists.org/t/some_thread_title/thread_index/30