I have uploaded a file to the group Code Samples files area called "A sequence
function for Excel.xls".

If anyone wants to have a look at it and tell me what you think, I would be
most interested.

If you want to use it please do. The only part I have protected is the
explanation sheet and that is not passworded.

I was concerned that looking at every cell in every used area of a spreadsheet
would take for ever so I included a progress report which tells you what it is
doing. If you want to see it saying anything other than "Completed!" you will
need to slow it down. You could uncomment the Application.Wait at line 51 so
it pauses for 3 seconds on each sheet, or you could fill the sheets with Seq()
formulae but it might still be too fast. I made it count up to 100,000 for
each cell and it hardly slowed it down noticeably.

I have not tested it with lots of invalid data.

If you find anything that could be improved or want explanations of any of the
parts, please let me know, either on or off list.