title: Multiply certain elements of a vector in R
body: <p>I have a vector [1:360] with integers and need to find the products of the first, second ... twelfth set of 30 elements. Ultimately, I need a function that gives me a vector [1:12] with the products of all twelve 30-element intervals.
  I'm fairly new to R and have been stuck on this for too long.</p>