$3^{n-1}$ Terms in a Group

Consider a group sequence of positive integers $(1),(2,3,4),(5,6,7,8,9,10,11,12,13), \dots,$ where the $n ^{\text{th}}$ group has $3^{n-1}$ terms in it. If $1068$ is the $b^{\text{th}}$ term of the $a^{\text{th}}$ group, what is $a+b$ ?