Increase the "resolution" of a vector?

Hey folks, there's something that I want to do but can't figure out how to get it.

As a simple example suppose I have a vector [1,4,7,2,4]. What I want to get is a vector of length N that "stretches out these elements.

So perhaps I want to get a 16 element vector [1,1,1,4,4,4,7,7,7,2,2,2,4,4,4,4].

How can I do this for a vector of general length?