4.12

#include <iostream>

using namespace std;
int main()
{
    double b1 = 0.5, b2 = 0.2, b;
    int n;
    cin >> n;
    for (int i = 3; i <= n; i++) {
        b = (pow(b2, 2) + b1 / (i-1));
        b1 = b2;
        b2 = b;
        cout << "i = " << i << "  "<< b << endl;
    }
    return 0;
}