Total height of all (unlabeled) rooted identity trees with n vertices.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =5a(5) =10a(6) =23a(7) =52a(8) =120a(9) =275a(10) =644a(11) =1508a(12) =3558a(13) =8418a(14) =20012a(15) =47699a(16) =114082a(17) =273476a(18) =657250a(19) =1582817a(20) =3819514a(21) =9233059a(22) =22356918a(23) =54216429a(24) =131663670a(25) =320158789a(26) =779461271a(27) =1899830067a(28) =4635492672a(29) =11321595218