by AuSmith » Wed Apr 04, 2007 10:28 am
Given any digit 0 through 9, there are always 4 digits that we can append on the left (all the odds below the given digit and all evens above). Therefore, if we construct a parity monotonic integer starting from the right, we have 10 choices for the first digit and 4 choices for each digit thereafter. If we want a parity monotonic integer of length four, we have [unparseable or potentially dangerous latex formula] distinct constructions.