485064009domain: NAppears in sequencesExpansion of g.f. (1-x^2)/(1-x-2*x^2+x^3).at n=35A028495Row sums of triangle A060556.at n=17A060557Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor.at n=8A221162