Auto-numbering fails

After data filtering, it seems that auto-numbering in column A is not
working when I select range A2 to A13 and double click the Fill Handle
at cell A13 , e.g..


Column A B
Row
2 1 AA
10 2 BB
13 3 CC
39 SS
116 SS
119 WW
225 OO
230 DD
305 CC

In this case, how to solve the above scenario with Excel function and
give the result with auto-numbering as follows : -

Column A B
Row
2 1 AA
10 2 BB
13 3 CC
39 4 SS
116 5 SS
119 6 WW
225 7 OO
230 8 DD
305 9 CC

Please help, thanks

Regards
Len