View Code of Problem 3695

#include <stdio.h>
#include <string.h>
#include <math.h>
#include<algorithm>
#include<string>
#include<stdlib.h>
#include<iostream>
using namespace std;
int main() {
	int t;
	scanf("%d", &t);
	while (t--) {
		long long a = 1, b = 2;
		int n;
		scanf("%d", &n);
		long long i, sum;
		if (n == 1) {
			printf("1\n");
		}
		else if (n == 2) {
			printf("3\n");
		}
		else {
			sum = 3;
			for (i = 3; i <= n; i++) {
				long long t = a + b;
				sum += t;
				a = b;
				b = t;
			}
			printf("%lld\n", sum);
		}
	}
	return 0;
}