This has been bugging me for something I was making so I did a small improvement on Mallika’s version. Using the RowIDs can work on new tables but can will random results if you have deleted rows before and doesn’t take into account your numbering pattern. Which is what I needed in my table.
So again the default value, like Mallika said, you could do:
Nth(thisTable.[Column 1],thisTable.[Column 1].Count())+1
This looks for the last row and does +1 on the number. You can spam the (+) button to add many rows.
This only works when you add new rows at the bottom of the table, one at a time.
It won’t work when you add multiple rows since they will all have the same number.
Hope this helps.