After receiving an inheritance of $50,000 on her 21st birthday, Kelly deposited the inheritance in a savings account with an effective annual interest rate of 4%. She decided to make regular deposits, beginning with $1,000 on her 22nd birthday, and increasing by $250 each year (that is, $1,250 on her 23rd birthday, $1,500 on her 24th birthday, etc.) What is the future worth of Kellys deposits on her 60th birthday? (I came up with an answer of 668,236...but I want to check my work.)