Mortgage Interest Rate Calculator

How do you figure amortization by hand without using a mortgage calculator?
Is there a formula that I could simply plug in numbers that would give me the The payment of $ 137,500 with a 5.25% interest for 30 years?
There is a formula, but I can not remember what it is. But if you make the loan to interest rate over 30 years, so take it! It is a great deal.