Jarmo, John has already given you some elisp code that can help. The other possibility could be to use the counter macro.
See the info manual: (org) Macro Replacement -- Eric S Fraga via Emacs 27.0.50, Org release_9.2.6-552-g8c5a78
- Continued lists Jarmo Hurri
- Re: Continued lists John Kitchin
- Re: Continued lists Samuel Wales
- Re: Continued lists Fraga, Eric
