How to create sequential email addresses

I am importing my customer list to a new system. It requires email addresses. We do not collect email addresses. Told to just create dummy names. So I want to add a column for each entry in Excel. Clients will have [John.Doe0001@noemail.com](mailto:John.Doe0001@noemail.com), [John.Doe0002@noemail.com](mailto:John.Doe0002@noemail.com) etc. How can I just run down the list doing this. There's a couple thousand entries I need to do this with. Use Excel via Office 365 on MacOs. I have tried fill handle and sequence fill and it does not do what I am looking for.