What is the correct formula for this question?

Question

A King in ancient times agreed to reward the inventor of chess with one grain of wheat on the first of the 64 squares of a chess board. On the second square the King would place two grains of​ wheat, on the third​ square, four grains of​ wheat, and on the fourth square eight grains of wheat. If the amount of wheat is doubled in this way on each of the remaining​ squares, what is the total weight in tons of all the wheat that will be placed on the first

5050

​squares? (Assume that each grain of wheat weighs​ 1/7000 pound. Remember that 1

tonequals=2000

​lbs.)

Answer 1

2^5049=100*10^498/7000=14.28571429*10^495lbs

/2000=7.142857143*10^492tons