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

Terms

a(0) =387420489a(1) =193710244a(2) =129140163a(3) =96855122a(4) =77484097a(5) =64570081a(6) =55345784a(7) =48427561a(8) =43046721a(9) =38742048a(10) =35220044a(11) =32285040a(12) =29801576a(13) =27672892a(14) =25828032a(15) =24213780a(16) =22789440a(17) =21523360a(18) =20390552a(19) =19371024a(20) =18448594