Number of 2n-node rooted trees of height n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =8a(4) =36a(5) =180a(6) =941a(7) =5079a(8) =27961a(9) =156129a(10) =880883a(11) =5009625a(12) =28668920a(13) =164897622a(14) =952418882a(15) =5520254925a(16) =32090787577a(17) =187030223470