300510domain: NAppears in sequencesa(n) = Sum_{k=1..prime(n)-1} floor(k^3/prime(n)).at n=27A078837Triangle read by rows: T(n,k) is number of hex trees with n edges and k nonroot nodes of outdegree 2.at n=34A126183G.f.: 1 + 1*x/(1 + 2*x^2/(1 + 3*x^3/(1 + 4*x^4/(1 + 5*x^5/(1 + ...))))).at n=30A343468