gistfile1.cpp

#include<iostream>
using namespace std;

int foo(int n)
{
    if (n == 0)
    {
        return 3;
    }
    if (n == 1)
    {
        return 2;
    }
    else
    {
        return foo(n-1) * foo(n-2) - n;
    }
}

int main()
{
    int n = 0, n1 = 0, n2 = 0, res = 0;
    cout << "cin n: ";
    cin >> n;
    if (n == 0)
    {
        n1 = 3;
    }
    if (n == 1)
    {
        n2 = 2;
    }
    int i = 0;
    while (n > 1)
    {
        if (i >= n)
        {
            break;
        }
        res = n1 * n2 - i;
        n1 = n2;
        n2 = res;
        i++;
    }
    cout << res;
}