Returning row numbers of a specific number that occurs multiple times in a column

Good Day All.

Example

A B
1 2 1
2 1 3
3 2 4
4 2 9
5 6
6 4
7 5
8 9
9 2

In the example above, 2 appears in cells A1,A3,A4 and A9. I need a formular that will return in column B the row numbers in which 2 appears in column A. Thank you.