Anyone know the answer to this?

Answer:
[tex]2^{n-1}[/tex]
Step-by-step explanation:
Square 1 has 2^0 pennies.
Square 2 has 2^1 pennies.
Square 3 has 2^2 pennies.
Square 4 has 2^3 pennies. The exponent of 2 is 1 less than the square number, so ...
Square n has 2^(n-1) pennies.