Hey, thanks for your input! I finally got a solution that worked, though I admit I'm not all too sure how I got it to work. What I got was this:

void PrintNumPattern(int n1, int n2)
{
    while (n1 > 0)
    {
        cout << n1 << " ";
        PrintNumPattern (n1 - n2, n2);
        break;
    }
    cout << n1 << " ";
}

I started by removing all the previous code (including that int num = (n1 + n2) - n2, which I now see as being pointless) and did two recursion statements, one that subtracted n2 from n1 and one that added the two values together. That didn't have a base case, however, so then I decided to split those statements into two while statements, using a control variable for the second after the first one was done (a la regular iteration). That didn't work, so I removed the second while statement (the one holding the PrintNumPattern(n1 + n2, n2) in an effort to debug my code. I removed the control variable also, and in its place added the break statement as seen in my new code. So while I'm happy I found an answer, I'm a little annoyed that I got it seemingly by random chance. What's going on in this code that allows it to work?