I concur with other comments, the database design is questionable from several angles.

As far as auto-numbering key values for the names, I feel this business rule might be better served outside the data layer.  If you must do this in the database, you could use a stored procedure to insert the rows and apply the logic there.  If you will be writing INSERT statements for this data, you could integrate a function to calculate this number.  A trigger could calculate the value after insert.  But regular "Auto Number" functionality is not designed to apply manipulative logic.

Here is a reason to NOT pursue this logic.  What if a user changes their name, and now it matches an existing name.  Your "auto number" is no longer unique.  If you've used this as a key in any way, now you have an integrity issue.  I'd stick with the identity value which will guarantee uniqueness across the entire solution.