Number of involutions of doubly alternating Baxter permutations of length n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =5a(8) =8a(9) =12a(10) =16a(11) =32a(12) =44a(13) =84a(14) =105a(15) =231a(16) =292a(17) =636a(18) =768a(19) =1792a(20) =2166a(21) =5080a(22) =6012a(23) =14592a(24) =17234a(25) =42198a(26) =49336a(27) =123088a(28) =143536a(29) =361190