I have a table:

table1

```
col1 col2
1    a
1    b
1    c

```

I want to add rownum but from a specific number, for ex. starting from 100, so it would look like:

```
col1 col2 rn
1    a    100
1    b    101
1    c    102

```

I know how to add rownum like below:

```
select a.*, rownum as rn from table1 a;

```

But I don't know how to add from a specific number. How to do it in Oracle SQL?