197139domain: NAppears in sequencesNumber of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.at n=16A209108G.f. A(x) satisfies: A(x - x^2 - x^2*A(x)) = x.at n=9A295539