Symmetrical dissections of an n-gon.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =5a(5) =14a(6) =14a(7) =39a(8) =42a(9) =132a(10) =132a(11) =424a(12) =429a(13) =1428a(14) =1430a(15) =4848a(16) =4862a(17) =16796a(18) =16796a(19) =58739a(20) =58786a(21) =208012a(22) =208012a(23) =742768a(24) =742900a(25) =2674426a(26) =2674440a(27) =9694416a(28) =9694845a(29) =35357670