Daily, I get calls from one of the following numbers. They leave no message and hang up if I answer.

412-396-2337
412-396-2343
412-396-5935
412-396-5936
412-396-5939
412-396-5941

I'm thinking it's a harmless telemarketer who gets paid for the number of calls made rather than sales.  Make it stop!

I saw another post for one of the numbers that it was argosy university but I can't confirm that.