3423112domain: NAppears in sequencesa(n) is the floor of the first component of M^n * (0, 1, 2, 3) where M is the matrix [[c, 1/2, 1/2, 1/2], [1/2, c, 1/2, 1/2], [1/2, 1/2, c, 1/2], [1/2, 1/2, 1/2, c]] and c=sqrt(3)/2.at n=17A121811