(In reply to
re: Two different exact answers by Charlie)
Thanks very much, Charlie.
In that case, the revised list of successively better methods is:
.00355081161408322 (reciprocal of expected number of occurrences) .00354451493749941 (complement of Poisson expectation of zero occurrences) .0035445212572191355 ( 1-(1-(1/6)^7)^994 )
.0035445968294705033 (Markov chain)