De bruijn Graph for Married Couples
We address the problemof enumeration of seating arrangements ofmarried couples around a circular table such that no spouses seat next to each other and no k consecutive persons are of the same gender. While the case of k = 2 corresponds to the classical probl`eme des menages with a well-studied solution, no closed-form expression for number of arrangements is known when k=3.
We propose a novel approach to this type of problems based on enumeration of circuits in certain algebraically weighted de Bruijn graphs. Our approach leads to a new expression for the menage numbers and their exponential generating function, and allows one to efficiently compute the number of seating arrangements in general cases. We work out all the details for k = 3.
