Second column of triangle A233530.

Terms

a(0) =1a(1) =2a(2) =3a(3) =8a(4) =38a(5) =268a(6) =2578a(7) =31672a(8) =475120a(9) =8427696a(10) =172607454a(11) =4008441848a(12) =104061288740