a(n) = binomial(n+8,8) * 2^n.

Terms

a(0) =1a(1) =18a(2) =180a(3) =1320a(4) =7920a(5) =41184a(6) =192192a(7) =823680a(8) =3294720a(9) =12446720a(10) =44808192a(11) =154791936a(12) =515973120a(13) =1666990080a(14) =5239111680a(15) =16066609152a(16) =48199827456a(17) =141764198400a(18) =409541017600