2014 Guts #13: Seating an Auditorium
Source:
April 20, 2014
countingdistinguishability
Problem Statement
An auditorium has two rows of seats, with seats in each row. indistinguishable people sit in the seats one at a time, subject to the condition that each person, except for the first person to sit in each row, must sit to the left or right of an occupied seat, and no two people can sit in the same seat. In how many ways can this process occur?