Number of planar tanglegrams of size n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =11a(4) =76a(5) =649a(6) =6173a(7) =63429a(8) =688898a(9) =7808246a(10) =91537482a(11) =1102931565a(12) =13594564857a(13) =170804438005