9514 1404 393
Answer:
1/3; geometric
Explanation:
Apparently, your sequence is ...
81, 27, 9, 3, 1, ...
The differences between these numbers vary, but the ratio of each to the one before is a constant:
27/81 = 9/27 = 3/9 = 1/3
The sequence is geometric with a common ratio of 1/3. The next number in the sequence is (1)(1/3) = 1/3.