a(n) = floor(9^n/n).

Terms

a(0) =9a(1) =40a(2) =243a(3) =1640a(4) =11809a(5) =88573a(6) =683281a(7) =5380840a(8) =43046721a(9) =348678440a(10) =2852823600a(11) =23535794706a(12) =195528140640