Find the 6th term of $1, ~ 2, ~ 5, ~ ... \, , ~ \frac{1}{2}(1 + 3^{n - 1})$.

Find the 6th term of $1, ~ 2, ~ 5, ~ ... \, , ~ \frac{1}{2}(1 + 3^{n - 1})$.

A. 111 C. 124
B. 136 D. 122

Solution