How many pennies are on the chessboard?

If the number of pennies doubles on each of the 64 squares, the counts are 1, 2, 4, and so on through 2^63. Their total is 1 + 2 + 4 + … + 2^63 = 2^64 − 1, so the correct choice is “2^64 − 1.”

AI-written and checked against the verified answer.