Project Euler - problem 16

2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26. What is the sum of the digits of the number 2^1000?

The result of (2^1000) is a number 303-digits long. Then you have to accumulate all the 303 digits.

In Python 3:

Good luck.