If you want to use all 3 columns, then it seems like this would work for
you:
D1: =$A$1&TEXT(B1,"0000")&$C$1
Then copy down column D.

But...
If you really only need the values in Cells A1 and C1 and just want to
increment the middle section, would this work?
D1: =$A$1&TEXT(ROWS($1:1)-1,"0000")&$C$1
(again, just copy that formula down column D)

Is either of thosse what you're looking for?

Ron