or x | y means x divides y. It also means that y is a multiple of x ie y = kx. Also x is a divisor of y. All these statements are equivalent and when working on these problems its useful to consider which one to work with.
But if you are having trouble with the question, with the criterion you have given i can tell you that if the coefficient of the polynomial is an and s|an for n=0,1,2,... then s | P(x).
But if you are having trouble with the question, with the criterion you have given i can tell you that if the coefficient of the polynomial is an and s|an for n=0,1,2,... then s | P(x).
Yep that basically indicates a sequence. The expression seems to be incomplete though - there should be some kinda criterion defining what kind of sequence that follows.