a(n) = (n+1)*binomial(n+1,8).

Terms

a(0) =8a(1) =81a(2) =450a(3) =1815a(4) =5940a(5) =16731a(6) =42042a(7) =96525a(8) =205920a(9) =413270a(10) =787644a(11) =1436058a(12) =2519400a(13) =4273290a(14) =7034940a(15) =11277222a(16) =17651304a(17) =27039375a(18) =40619150a(19) =59942025a(20) =87026940a(21) =124472205a(22) =175587750a(23) =244550475a(24) =336585600a(25) =458177148a(26) =617310936a(27) =823753700a(28) =1089372240