Mai and Andre found an old, brass bottle that contained a magical genie. They freed the genie, and it offered them each a magical $1 coin as thanks. The magic coin turned into 2 coins on the first day.
The 2 coins turned into 4 coins on the second day.
The 4 coins turned into 8 coins, on the third day.
This doubling pattern continued for 28 days.
The number of coins Mai had on the 28th day is very, very large. Write an expression to represent this number without computing its value.