Originally Posted by Spencer101

If you write the formula in the first row then highlight that cell and the one below, you can just drag the two down to copy. That will put the formula in all the even numbers (for example) and leave the odd ones blank.

It will also work if you have two formulas that you want to alternate all the way down. Put formula one in the first row and formula two in the second, highlight the two cells and drag down as necessary.

Hope that helps.