HDU-2077

点击打开链接

#include<stdio.h>
int main(void){
int t,n,i,a[21]={0,2};
    for(i=2;i<=20;i++)a[i]=3*a[i-1]+2;
while(scanf("%d",&t)!=EOF){
    while(t--){
        scanf("%d",&n);
        printf("%d\n",a[n-1]+2);
    }
}
return 0;
}