Excel - excel formula for markup and profit margin

I would like to input a cost price, say in cell A1
then
B2 a 5% markup, B3 then would show the sell price, B4 would show the margin
C2 a 10% markup, C3 the sell price, C4 margin
etc all the way to 100% in 5% increments

In short i'm looking for an easy way to calculate a realistic sell price
based on a margin

In B2:
=$A$1*0.05*COLUMNS($A:A) and copy across
In B3:
=$A$1+B2 and copy across
In B4:
=B2 and copy across

ok