11691702domain: NAppears in sequencesNumber of hex trees with n edges and having no nonroot nodes of outdegree 2.at n=14A126184a(n) = (1/2)*n*(n-1)*3^(n-1).at n=12A129530Row sums of A211230.at n=27A211231Expansion of Product_{k>=1} (1 - 3^(k-1)*x^k).at n=17A352786