Odd PR Numbers

[rogerd]

I've looked at a site that has an odd PR breakdown. Home page is showing as PR5, but a site-map-type page is at PR6. Virtually all external links (hundreds) go to the home page. Couldn't find any external links at all to the site map page. Both the home page and site map are linked from a navigation table on every page (along with other pages).

The site map is not optimized in any way, i.e., there's a couple of hundred links to pages on the site with almost no text outside the links (it's not a complete site map, more of a category map).

I'm at a loss as to how the site map can outrank the PR of the home page. Could the mass of links to other pages on the site make it look like an important hub of some kind? And how would that affect PR?

Maybe one of you math majors that loves third-order differential equations can explain this one... ;)