The sequence is: 1, 2, 3, 18/5, 18/5, 108/35, 81/35, 54/35, 162/175.....etc.
This is a sequence of "rising factorials" beginning as follows: a(n) =6^(n -1) / 3(n - 1). Sometimes a(n) is called "Pochhammer symbol". For example: the 6th term is arrived at, according to the formula above, as follows: 6^(6 - 1) / (3.4.5.6.7) =7,776 / 2,520 = 108/35.