405024domain: NAppears in sequencesNumber T(n,k) of permutations of {0,1,...,2n} with first element k whose sequence of ascents and descents forms a Dyck path; triangle T(n,k), n>=0, 0<=k<=2n, read by rows.at n=27A316728Number of (undirected) Hamiltonian paths on the first n cells of the 3 X ceiling(n/3) knight graph.at n=40A389759