Triangulations of the disk G_{2,n}.

Terms

a(0) =1a(1) =6a(2) =21a(3) =88a(4) =330a(5) =1302a(6) =5005a(7) =19504a(8) =75582a(9) =294140a(10) =1144066a(11) =4458192a(12) =17383860a(13) =67866918a(14) =265182525a(15) =1037169760a(16) =4059928950a(17) =15905412468a(18) =62359143990a(19) =244662838160a(20) =960566918220