All radial engines have odd number of cylinders on each row so that the firing order can be every other cylinder. i.e. 1-3-5-7-2-4-6.
However I remember reading a paper presented to the RAeS titled "By The Application Of Power".
In this paper a 32 cylinder 4 row radial built by Allison (I think) was mentioned. I don't know how the firing order would have worked.