Number of plane binary trees of size n+3 and height n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =4a(4) =68a(5) =376a(6) =1440a(7) =4736a(8) =14272a(9) =40576a(10) =110592a(11) =291840a(12) =750592a(13) =1890304a(14) =4677632a(15) =11403264a(16) =27443200a(17) =65306624a(18) =153878528a(19) =359399424a(20) =832831488a(21) =1916272640a(22) =4380950528a(23) =9957277696a(24) =22510829568a(25) =50642026496a(26) =113413980160