Setting up a cyclic sequence generator without holes

I am trying to set up a sequence that assigns values within a specific range, say 1-99.   But, for my particular application, I need the ability to de-allocate a number that was previously assigned, say 27.  Then, when we hit 99, I want the sequence to start cycling through the holes (and pick 27 next, assuming there were no other de-allocations).  I don't want the sequencer to simply cycle back through numbers already in use.

Has anyone else done this or know any tricks?  Otherwise, it looks like I will just have to make my own sequencer.  Thanks.

- Leon Starr