adding a number to variables

[Breinn]

I have a table that is like this

1
1
1
2
2
3
3
3
3

I would like it to look like this

1 1
1 2
1 3
2 1
2 2
3 1
3 2
3 3
3 4

any easy formula for that?

TIA

 

[Bob Phillips]

B1: 1
B2: =IF(A2=A1,B1+1,1)

and copy down