Number of rooted identity (asymmetric) planar trees that can be turned over.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =6a(6) =25a(7) =92a(8) =341a(9) =1225a(10) =4366a(11) =15522a(12) =55312a(13) =197965a(14) =712244a(15) =2577106a(16) =9375361a(17) =34284972a(18) =125977465a(19) =464938190a(20) =1722817416a(21) =6407307544a(22) =23909159418a(23) =89491715106a(24) =335908316845