http://pentaxplus.jp/index.html
(in Japanese)
A quick check on the registration information confirms that this web domain was registered and is still being held by the "Pentax Ricoh Imaging Company Co, Ltd." which was also renamed anyway.
It is noted that the registration will soon expire by fall March this year. Hope that this last official "Pentax" website will be kept. Nonetheless, some photos in this website are great and worth a look.
Related:
PENTAX is Gone! >:-(
The Name PENTAX is Dismissed from the Cyber Space! >:-(