Column 1 of triangle A185628.

Terms

a(0) =1a(1) =3a(2) =12a(3) =55a(4) =315a(5) =2243a(6) =19378a(7) =198363a(8) =2358860a(9) =32060736a(10) =491393909a(11) =8398281337a(12) =158541018923