78643200domain: NAppears in sequencesExpansion of (1 - 2x + 2x^2 - x^3)/(1 - 2x)^2.at n=23A084860Expansion of x^4*(5 - 16*x + 13*x^2)/(1 - 2*x)^4.at n=21A268587Consider the Watanabe tag system defined in A291067; a(n) = number of binary words of length n which terminate in a cycle.at n=26A291781