a(n) = (10*n + 9)^4.

Terms

a(0) =6561a(1) =130321a(2) =707281a(3) =2313441a(4) =5764801a(5) =12117361a(6) =22667121a(7) =38950081a(8) =62742241a(9) =96059601a(10) =141158161a(11) =200533921a(12) =276922881a(13) =373301041a(14) =492884401a(15) =639128961a(16) =815730721a(17) =1026625681a(18) =1275989841a(19) =1568239201a(20) =1908029761a(21) =2300257521a(22) =2750058481a(23) =3262808641a(24) =3844124001a(25) =4499860561