How do I write an IF statement for number sequencing?

[Sampoline]

How do I write a formula that achieves Column B? When a blank cell appears in Column A, Column B must also leave the cell blank. But on the next cell if there is a filled cell in Column A, it must continue the number sequence from where it was last left in Column B.

 

[mrshl9898]

Would this do the job?

=IF(A2="","","xxx_"&TEXT(COUNTA(A$2:A2),"0000"))

 

[Sampoline]

Would this do the job?

=IF(A2="","","xxx_"&TEXT(COUNTA(A$2:A2),"0000"))

Hi mrshl, this does work. Thanks for your reply. Just wondering how I would fix this now:

Need column E to use Column C to skip whenever it is "Y".

So in the above example for Column E: ABC123_0001_m, ABC123_0002_m, ABC123_0003_m, SKIP (because "Y" exists in Column C), ABC123_0004_m

How do I get this to work if you have any ideas?

 

[maabadi]

Use this for column D (D2) and drag it down:

=IF(C2="y","",A2&TEXT(ROW()-1-COUNTA(C$2:C2),"0000"))

And for column E (E2):

=IF(C2="y","",A2&TEXT(COUNTIF($A$2:A2,A2)-COUNTA(C$2:C2)+COUNTBLANK($E$1:E1),"0000")&"_m")