Excel - How to repeat multiple functions

Hello,

I'm trying to set up a spread sheet in excel. Following is an example.

A1 is say 500
B1 is say 50 and is a number from a IRS table that changes as you get older
C1=A1/B1 for this example: 500/50 equals 10
D1 =A1*.04 for this example: 500 times .04 equals 20

A2 = A1-B1+C1 in this example: 500-10+20 equals 510
A3 = A2-B2+C2 in this example 510 -[510/48(from IRS table)equals 47.65] + [510*.04 equals 20.4]
A4 = A3-B3+C3
A5 = A4-B4+C4 etc.

Is there an easy way to calculate A3 to A20 using the "A" value from the previous row i.e.
A3 is computed using A2,
A4 is computed using A3,
A5 is computed using A4 etc.?

Any help you can provide will be appreciated.

Thank you, jksilva

P.S. Great web site!