Column k=9 of triangle A257673.

Terms

a(0) =1a(1) =27a(2) =378a(3) =3681a(4) =28134a(5) =180198a(6) =1007370a(7) =5051790a(8) =23173047a(9) =98644395a(10) =394006761a(11) =1489460724a(12) =5365964511a(13) =18526724685a(14) =61587671283a(15) =197885754837a(16) =616568620176