View Code of Problem 73

#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    int day=n-1;
    int x2=1;
    int x1;

    while(day>0)
    {
        x1=(x2+1)*2;
        x2=x1;
        day--;
    }
    printf("%d",x1);
}