46008619domain: NAppears in sequencesExpansion of g.f. (1-x^2)/(1-x-2*x^2+x^3).at n=31A028495Row sums of triangle A060556.at n=15A060557Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor.at n=7A221162