The sequence $2,4,8,16,32,64,...$ is
known referred to as the binary sequence. So perhaps "element of the binary sequence" will fit your requirements suffice given adequate context.
EDIT: Clearly, the set $B$ of all persons using the term binary sequence for $1,2,4,8,...$ is non-empty. The book linked in MJD's comment is one I taught from for many years, and I suspect many students and teachers have encountered this book. I will admit that this author did stretch several conventions in order to appeal to his unsophisticated audience, but I am certain this is not the only place I have seen this usage.
This appears to be yet another case in mathematics where a term is used differently in different contexts (the word "normal" being perhaps the most abused term in all of mathematics). Anon's comment and my Google searching reveal that the set $B$ I mention seems to be a distinct minority amongst a super-set of all persons who use the term 'binary sequence' in any way.
However, I argue that this does not justify saying that this usage is non-standard or idiosyncratic. Merely less common.
So getting back to the OP's question, you can use my original answer, but you will have to ensure your audience understands your meaning.