Unwanted phone calls multiple times a day for months from this number: 206-897- (X)
X=  0639, 0619, 2100, 0549, 0636, 0509, 0532, 0603

I have called a couple of them back and I believe they are coming from the University of Washington.
When I answer I get the following:
1. The call is dropped, as if someone is hanging up on the other end.
OR
2. It's an automated service asking about a message for "Roderaton". Then they give me two options: press 1 if you know the person or something like that or press 2 if this person is not known to you.