Number of Sós permutations of {0,1,...,n}.

Terms

a(0) =2a(1) =6a(2) =16a(3) =30a(4) =60a(5) =84a(6) =144a(7) =198a(8) =280a(9) =352a(10) =504a(11) =598a(12) =812a(13) =960a(14) =1152a(15) =1360a(16) =1728a(17) =1938a(18) =2400a(19) =2688a(20) =3080a(21) =3450a(22) =4128a(23) =4500a(24) =5200a(25) =5724a(26) =6440a(27) =7018a(28) =8100a(29) =8618