For starters, I highly recommend Gary's approach as it is a non-volatile solution. I will be providing an offset solution to match your initial thought process. However I do not recommend using it if you have a lot of offset or other volatile functions in your workbook as they can cause things to slow down significantly after a certain number of them. Volatile formulas recalculate every time something on the worksheet changes, where a non volatile functions only recalculates when the ranges it refers to change.
=OFFSET(A1,2*(ROW(A1)-1)+1,0,1,1)
Place that where you want your data to start and copy down as far as required.