Nested loop problem

[jim01]

I am completely lost on this particular program. I am supposed to write a program that finds the monthly payment for 30 years, for principals from
$100,000 through $200,000(with increments of $20,000) and interest rates of
6% through 10% (with increments of 0.5%). The output of the file must be in a table that looks something like this:

Principal 6% 6.5% 7% 7.5% 8% 8.5% 9% 9.5% 10%
100000 600 632 665 699 733 768 804 840 877
120000 719 758 798 839 880 922 965 1009 1053
140000 … … … … … … … … …
160000 … … … … … … … … …
180000 … … … … … … … … …
200000 … … … … … … … … …

The monthly payment on mortgage loan of L dollars, at a rate of interest r is given by:

Monthly payment = [L(1 + r/12)exponent 12N ]/[(1 + r/12)exponent 12N - 1]

where N = number of year mortgage (30 years).

The professor gave us this hint:

Hint: Use the following idea to compute (1 + r/12)exponent 12N
double temp = 1+r/12;
double temp1 = 1;
for (int i = 1; i<=12*N;i++)
{
temp1 = temp1*temp;
}
The final formula now becomes:
double mp = (L*(r/12)*temp1)/(temp1-1);

I have no idea where I am supposed to use this. Here is what I have:

public class ProgrammingProblemTwo {

    public static void main(String[] args){

    	//declare variables
		double r = 0, N = 0, monthlyPayment = 0;

		double temp1 = 1;
		double sum;
		double temp = 1 + r / 12;

		System.out.println("Principal   6" + "%" + "   6.5" + "%" + "   7" + "%" +
			 "   7.5" + "%" + "   8" + "%" + "   8.5" + "%" + "   9" + "%" + "   9.5" +
			 	 "%" + "  10" + "%\n");

		//create loop to increment principal in dollars, L
    	        for(int L = 100000; L <= 200000; L += 20000){
    		System.out.println(L + "\n");

    		//create loop to increment interest rate, r
    			for(r = .06; r <= .101; r += .005){

    				//create (1 + r / 12) exponent 12N formula
					for (int i = 1; i<=12*N;i++){
						temp1 = temp1*temp;
						monthlyPayment = (L*(r/12)*temp1)/(temp1-1);
					}
				}
		System.out.println(L + monthlyPayment + "\n");
    	}
    }
}

I have tried putting "System.out.println(L + monthlyPayment + "\n");" within the brackets of each for loop with no success. I've been messing with this for several hours now and I'm at a loss. I'm pretty sure I have the loop for my principal (L) and the rate of interest (r) correct.