Number of rooted identity trees with 2n nodes.

Terms

a(0) =0a(1) =1a(2) =2a(3) =6a(4) =25a(5) =113a(6) =548a(7) =2770a(8) =14426a(9) =76851a(10) =416848a(11) =2294224a(12) =12780394a(13) =71924647a(14) =408310668a(15) =2335443077a(16) =13446130438a(17) =77863375126a(18) =453203435319