How many 7s in the following number sequence are immediately preceded by 1 and not immediately followed by 3?
9, 8, 5, 1, 7, 3, 1, 7, 6, 5, 6, 3, 7, 7, 1, 4, 6, 1, 7, 5, 9, 3, 1, 7, 4, 4, 6, 1, 7, 3, 3, 7, 8, 1, 7, 2