I need help answering this problem:

A sequence of 8 annual payments of $750 each, with the first payment due at the beginning of the 6th year; money is worth 6%. (The beginning of year 6 is the end of year 5.) Find the present value.

This is my answer: 750 [ (1-1.06^-13) / .06 ] - 750 [ (1-1.06^-5) / .06 ] = $3,480.24

and this is the book's: $3,689 .

The book didn't provide a solution, so I would really appreciate it if someone can help me find where my solution went wrong. Thank you!