ACMSTEP 3.1.4 Tiling_easy version //递推

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;

int a[50];

void init()
{
int i;
a[0] = 1;
a[1] = 1;
a[2] = 3;
for(i = 3; i < 31; i++)
{
a[i] = 2 * a[i - 2] + a[i - 1];
}
}
int main()
{
init();
int n, cases;
cin>>cases;;
while(cases--)
{
cin>>n;
cout<<a
<<endl;
}
return 0;
}