> 代码如下：
> 
> #include"stdio.h"
> #include"math.h"
> 
> void main()
> {
> 	int n, t;
> 	long ans;
> 	scanf("%d", &t);
> 	while(t--)
> 	{
> 		scanf("%d", &n);
> 		ans = (long)pow(2, n-1) + (long)pow(4, n-1);
> 		printf("%ld\n", ans);
> 	}
> }