~cpp
#include <iostream>
using namespace std;
#include <vector>
int count;
unsigned int n[1001] = {1,2,5,};
int convert(int num)
{
int temp = num;
int l = 1;
for(int i = 0; i < 3; i++)
{
if(temp%10 == 4)
num -= 3*l;
temp /= 10;
l *= 10;
}
return num;
}
int main()
{
int num;
vector<int> test;
for(int i = 3; i <= 1000; i++)
n[i] += 2*n[i-1] + n[i-2] + n[i-3];
for(int k =1; k < 30; k++)
cout << n[k] << endl;
while(cin >> num)
{
// num = convert(num);
test.push_back(num);
}
for(vector<int>::iterator j = test.begin(); j != test.end(); j++)
cout << n[*j] << endl;
return 0;
}