Q_n(2) (see A104035).

Terms

a(0) =1a(1) =2a(2) =9a(3) =58a(4) =501a(5) =5402a(6) =69909a(7) =1055458a(8) =18211401a(9) =353506802a(10) =7624471809a(11) =180889942858