Number of centrally symmetric Baxter permutations of length n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =6a(5) =8a(6) =26a(7) =38a(8) =130a(9) =202a(10) =712a(11) =1152a(12) =4144a(13) =6904a(14) =25202a(15) =42926a(16) =158442a(17) =274586a(18) =1022348a(19) =1796636a(20) =6736180a(21) =11974360a(22) =45154320a(23) =81040720a(24) =307069360a(25) =555620080a(26) =2113890560a(27) =3851817920a(28) =14705955008a(29) =26960013552