I've possibly been confusing with the use of the word iterate. The list is actually directly accessible. I can access element x cheaply and statelessly - the records are fixed sized and contiguous.

I just want to walk this list in a well-defined, reproducible, random-order.

I think multiplying by a prime and then dividing by the maximum has something to do with producing the 1-1 mapping (was it RSA or abstract algebra / group/ring theory - I'm too old for this sh*t).

-Andrew.