Answer:
The sequence is the ratio of 4:8, or 16:32. This is because the sequence needs to be divided into 2 different factors in order for it to match. The sequence is...
add 4, add 8, add 16, continue on.
The formula is...
4 * x = sequence
In this case, x is the increasing factor. I substituted it due to the fact that it's a constantly increasing number, not just a straight-up number we can declare.