a(n) = (n+8)!/8!.A049389a(n) = (n+8)!/8!.Terms a(0) =1a(1) =9a(2) =90a(3) =990a(4) =11880a(5) =154440a(6) =2162160a(7) =32432400a(8) =518918400a(9) =8821612800a(10) =158789030400External referencesoeis: A049389