Indexes not being analyzed for optimizer statistics

I have an issue in my database where my tables are being analyzed each night and those that have a change of 10% or greater are getting their statistics updated.  What I am not seeing is the indexes being analyzed.  One set of indexes for a table, that was last analyzed on Nov 4, shows the indexes were last analyzed on Oct 11. The statistics show that they are stale but still not getting analyzed.  Is there a setting or something to make sure the indexes get analyzed?  I thought the auto optimizer would also update the index statistics.

Any help is greatly appreciated, I've tried google and oracle documentation but I have not found an answer.