nth term question

Question

what is the nth term of 1, 4, 16 ia ??

Answer 1

This looks like a geometric series with a common ratio of 4.

1st term: 1 = 4⁰ = 4^1-1

2nd term: 4 = 4¹ = 4^2-1

3rd term term: 16 = 4² = 4^3-1

^

Do you see the pattern?

nth term: 4^n-1