此题建议使用查表法233333333

 include<iostream>
 include<vector>
 using namespace std;
 vector arr = { 6, 28, 496, 8128 };
 int main()
 {
     int n = 0;
     while (cin >> n)
     {
         cout << n << ":";
         for (int i = 0; i < arr.size(); i++)
         {
             if (arr[i] <= n) cout << " " << arr[i];
         }
         cout << endl;
     }
     return 0;
 }