13153337344domain: NAppears in sequences4th binomial transform of (1,3,0,0,0,0,0,.....).at n=15A081039a(n) = n^2*4^n/4.at n=14A086952Expansion of g.f. (1 - x)^2*(1 + x) / (1 - 2*x)^2.at n=30A106472Consider the Post tag system defined in A284116; a(n) = number of binary words of length n which terminate in a cycle.at n=33A289671