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

Terms

a(0) =9a(1) =41a(2) =243a(3) =1641a(4) =11810a(5) =88574a(6) =683282a(7) =5380841a(8) =43046721a(9) =348678441a(10) =2852823601a(11) =23535794707a(12) =195528140641