How can I copy/paste the *formatting* of a table in Powerpoint?
As far as I know, what you are asking for is not possible.
If all your tables are to have the same style, you could create a presentation template that has this one style as default table style.
Another option is to copy the table out of PowerPoint into some other Office application such as Word or Excel that is more flexible, then copy it back.
The simplest way is to just copy the whole slide and then delete the text that you don't want. That way you have an identically formatted table to work off of.