It looked like this. You have a Discrete signal. So I'm using both the signal notation and vector notation here, and I'll continue to do that, sort of mix the two up, because I think they're both useful. So the idea is you have either an N-tuple of numbers or a Discrete signal whose value at the nth point is just the value here, FM. Okay? Oops, that doesn't look right. That's not much of a statement. So you can either consider it as a Discrete signal who's defined on the integers or the integers from zero to N minus one, or you can think of it as an N-tuple or as a vector. ...

See the whole transcript at The Fourier Transform and its Applications - Lecture 21