Explicit formulas for geometric sequences

Solve problems such as: The first four terms in a geometric sequence are 1/3, 1, 3, and 9. Find an explicit formula for the sequence.
You might need: Calculator

Problem

g is a function that describes a geometric sequence, and is therefore defined over the positive integers. Below are the first few terms of the sequence.
n1234
g, left parenthesis, n, right parenthesis31575375
Find an explicit formula for g, left parenthesis, n, right parenthesis.
space, g, left parenthesis, n, right parenthesis, equals