a(n) = (10*n + 9)^2.

Terms

a(0) =81a(1) =361a(2) =841a(3) =1521a(4) =2401a(5) =3481a(6) =4761a(7) =6241a(8) =7921a(9) =9801a(10) =11881a(11) =14161a(12) =16641a(13) =19321a(14) =22201a(15) =25281a(16) =28561a(17) =32041a(18) =35721a(19) =39601a(20) =43681a(21) =47961a(22) =52441a(23) =57121a(24) =62001a(25) =67081a(26) =72361a(27) =77841a(28) =83521a(29) =89401