Which quantity is greater? (2)

In the sequence $a_1,a_2,a_3,\dots,a_n,\dots,$ and $a_1=4$ and each term after the first term is equal to the preceding term plus $6.$

In the sequence $b_1,b_2,b_3,\dots,b_n,\dots,$ the $n^{th}$ term of the sequence is given by the formula $b_n=2^{n-1}$

Quantity A: $a_{43}$

Quantity B: $b_9$