APEX

I would like to know how I can (dynamically) have a row number in a column in an Interactive Report? It is a computation, if so what should it look like?

It should be as such that the row starts with the row number from 1 to n sequentally, always in a complete sequence regardless of the filtered results, e.g.

1 Tom
2 Donald
3 Harry
4 Fred
...
n

(This should not be confused with ROWNUM or ROWID.)

Thanks.