View Code of Problem 3834

#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <stack>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

int main() {
	int n;
	long long arr[35];
	arr[0] = 0;
	arr[1] = 2;
	arr[2] = 5;
	for (int i = 3; i < 35; i++) {
		arr[i] = arr[i - 1] * 3 - 1;
	}
	while (cin >> n) {
		cout << arr[n] << endl;
	}
	return 0;
}