Column 1 of triangle A109282.

Terms

a(0) =1a(1) =2a(2) =6a(3) =36a(4) =258a(5) =2190a(6) =20988a(7) =222042a(8) =2554890a(9) =31606740a(10) =416907618a(11) =5824488540a(12) =85725372240