Thread: (a,b,0) class distributions

Hi all,
I have a question regarding (a,b,0) class distributions. I know that there are 3 distributions which are classified in this category, which are Poisson dist, Negative Binomial dist and Binomial dist.
However, I have been told that there may be another 1 distribution which is classified in this category. Does anyone know which is the other one

Thanks a lot!

Not that I know of...