Random events (as we understand them here) are completely
unrelated to one another.
So the answer is to pre-load your system with 1,
and have all the other values be random.
[random 5]
|
[t b f]
X
[f 1]
will always start with 1, and then give you random numbers.
BUT:
It might also give you, 1, 1, 1, 1....
I suspect what you really want is to replace the random
with an urn.
a.