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COMMENTS
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A Marf-Low rule is coded in a 3-digit base-10 integer abc where neither a nor b = 0. A sequence of integers is then produced by the following rule.
The abc integer is interpreted like this:
a = a(1) [taken in the set 1,2,3,4,5,6,7,8,9],
b = a multiplicative factor [taken in the same set],
c = a stop-digit [taken in the set 1,2,3,4,5,6,7,8,9,0].
For example, the Marf-Low rule 173 produces the sequence:
S = 1, 7, 49, 343, 2, 14, 98, 686, 4802, 33614, 3, 4, 28, 196, 1372, 5, 35, 6, 42, 296,...
Explanation:
# Start with a(1) = a [here a(1) = 1]
# If a(n) doesn't contain the stop-digit c, then a(n+1) = 7*a(n) [this is the case here, as 1, not having any digit 3, is then multiplied by 7, producing a(2) = 7]
# otherwise a(n+1) is the smallest integer not yet in the sequence.
The rule 173 produces indeed 1, 7, 49, 343 which stops, and restarts with 2, 14, 98, 686, 4802, 33614, which stops and restarts with 3, which stops and restarts with 4, 28, 196, 1372 which stops and restarts with 5, 35 which stops, ...
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