Number of (2n+1)-node rooted identity trees of height n.

Terms

a(0) =1a(1) =0a(2) =0a(3) =2a(4) =12a(5) =61a(6) =301a(7) =1460a(8) =7019a(9) =33628a(10) =160934a(11) =770109a(12) =3686706a(13) =17661288a(14) =84675601a(15) =406319271a(16) =1951428049a(17) =9380072046a(18) =45124798445a(19) =217252113080