Write a program to output the first 55 perfect numbers. A perfect number is defined to be a positive integer where the sum of its positive integer divisors excluding the number itself equals the number.

For example: 1+ 2 + 3 = 61+2+3=6, and 66 is the first perfect number.

There is no input for this problem.

题意：输出前5个完美数
思路：如果p是质数，且2^p-1也是质数，那么（2^p-1）* 2^（p-1）便是一个完全数。
枚举p，然后判断质数就可以了

#include <bits/stdc++.h>
using namespace std;
int main() {
	cout << "6"<<endl;
	cout <<"28"<<endl;
	cout <<"496"<<endl;
	cout <<"8128"<<endl;
	cout <<"33550336" <<endl;
	return 0;
}