Looking for next number in sequence

[Alex.W]

I am looking for a cell formula that will look for the largest number in
column "A" in another sheet and return the next number in the sequence.

 

[Gary''s Student]

=MAX(Sheet2!A:A)+1

 

[Ember]

Any suggestions on how to make this work when your cells have text?

At the top of my spreadsheet I have a cell that indicates the next number to
be used. This is because the entries are sorted by a field other than this
identifier, and new entries are added after a row has been inserted in the
correct place. Therefore, the cell at the top is important to know what next
number can be used.

The format for the "number" is C00001, C00002, C00003, ect. the =MAX(A:A)+1
solution does not work for me because the prompt inidactes that it will
ignore text.

Thanks!