111658domain: NAppears in sequencesNumber of series-reduced balanced trees with n leaves.at n=30A120803Number of length-n binary vectors beginning with 0, ending with 1, and avoiding 4 consecutive 0's and 4 consecutive 1's.at n=21A283834Expansion of 1/sqrt(1 - 4*x/(1 - x^2)^2).at n=9A376810