Bijective issues around Dyck paths, ordered trees, binary trees are reviewed, as non-specialists are probably not familiar with them. Then structures enumerated by the sequence 1,1,3,10,36,137, 543, 2219, … are discussed, among them skew Dyck paths, marked ordered trees, unary-binary trees, Hex-trees, 3-Motzkin trees. It is demonstrated how to derive relevant generating functions. Bijective issues are also discussed.
