The pattern is given below
1, 3, 9, 27
We can clearly see that the terms are indeed the powers of 3
i.e

looking closely at the sequence generated, we can show that it follows the geometric sequence as

Thus, the common ratio r equals

for any two consecutive numbers in the sequence
Hence, we can express the sequence as a numeric sequence thus:

We can also create a table of values to show that this sequence follows the geometric sequence