1: #include <stdio.h>
2: #include <math.h>
3:
4: int main()
5: {
6: double sum = 0;
7: int i;
8: for (i = 1; i <= 64; ++i)
9: {
10: sum += pow(2, i-1);
11: }
12: printf("the sum is \n%f\n", sum);
13:
14: return 0;
15: }