On Thu, 1 Jan 2009 14:39:59 -0500, "T. Valko" wrote:

**Assuming no numbers are duplicated.**

That's the key point, of course



A more efficient error trap for versions prior to Excel 2007 might be:

=IF(ROWS(B$2:B2)<=MAX(Order)-MIN(Order)+1-COUNT(Order),.....

I really like the IFERROR function in 2007.
--ron