1 / 3, 5 / 9, 19 / 27. What is the eighth number?

1 / 3, 5 / 9, 19 / 27. What is the eighth number?

From the molecule, we can see that it's 3 ^ 1 3 ^ 2 3 ^ 3
The difference between the denominator and the cent is 2.48, which can be written as 2 ^ 1.2 ^ 2.3
So the eighth number is (3 ^ 8-2 ^ 8) / 3 ^ 8 = 6305 / 6561