a(n) = Bell(n)*Motzkin(n).

Terms

a(0) =1a(1) =1a(2) =4a(3) =20a(4) =135a(5) =1092a(6) =10353a(7) =111379a(8) =1337220a(9) =17657745a(10) =253753300a(11) =3934348860a(12) =65357103067