Hi,

I am trying to generate a unique ID in Google Sheets.

The structure of the unique ID is the following:

2x Letter values (A-Z)+ 2x Digit values (18,19 or 20) + 2x Alphanumeric (A1,A2...Z9).

With the above, an example unique ID will look like this: GB18A1

I would like the last 2 alphanumeric characters to be generated in sequence (A1, A2.. A9, B1, B2.. B9...) and taking into account previous 4 characters, since the sequence is dependent on the first 4 characters and does not run independently.

So, when someone is creating a new ID with first 4 characters being LD18, sequence will start from A1. Next time some creates an ID with LD18 as first 4 characters, A2 will be spit out. But if first 4 characters are changed, sequence will have to start from A1 again.

I am unable to post a link but will do so if it's required (my forum access rights do not allow me to post links yet)