113031domain: NAppears in sequencesNumber of loopless tree-rooted planar maps with 3 vertices and n faces and no isthmuses.at n=17A006428Fibonacci sequence beginning 6, 13.at n=20A022388Number of n X 3 0..1 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=18A223765