Validating missing numbers (highlighting comparison column)

I have a range of numbers in column A which started with number 2 through 65535. This range is missing numbers. (For instance, numbers 1, 6, and 7, are missing from this range.

What we want to know is using Excel 2003, steps on How to Set up a Formula that will either highlight the missing numbers from a complete "non-gapped range of numbers" in column B, or either a formula that will tally Column A and place missing numbers (gaps) in another column.

Again, our range starts like:

2
3
4
5
8
9
10
12
14
15
16
17
18
19
20
22
26
28
29

So we know card 1, 6, 7 13, 21 23, 24, 25 and 27 are not in column A. Our range is a 2000 count range so we can't sit and manually count what is missing. Your help with a formula would help me tremendously.

FDibbins-thank you for your reply. Yes the numbers are sequential. It's a compilation of numbers derived from several databases whereas we are trying to find out which numbers are not in use. My list is a numbers of just that (Numbers not being used). However the issue is: I need to ask a supplier to replenish 2000 items using numbers in my range - but I must provide to them an exclusion list which will = the gaps (missing numbers from column A). I am not familiar enough with formulas to know how to build the formula.

Looks like FDibbins may be offline. Try this:

With your numbers starting in A2 place this in B2 and drag down:

=IF(A2-A1=1,"",IF(A2-A1=2,A2-1,MAX(A$1:A1)+1&"-"&A2-1))

Absolute genius!!! Thanks so much; it works out well with minor editing. <I wanna be like you when I grow up.>

I think I got it marked properly. Good night.

Thanks again to you both.