Suppose you have a 3 x 3 checkerboard (so it has 9 squares). You put one penny on the first square, then 3 pennies on the next square, then 32 pennies on the next square, and so on until there are pennies on all nine squares. Write an expression that gives the total number of pennies on the board. Find the sum

Suppose you have a 3 x 3 checkerboard (so it has 9 squares). You put one penny on the first square, then 3 pennies on the next square, then 32 pennies on the next square, and so on until there are pennies on all nine squares. Write an expression that gives the total number of pennies on the board. Find the sum