a(n) = 100*n^2 - 10.

Terms

a(0) =90a(1) =390a(2) =890a(3) =1590a(4) =2490a(5) =3590a(6) =4890a(7) =6390a(8) =8090a(9) =9990a(10) =12090a(11) =14390a(12) =16890a(13) =19590a(14) =22490a(15) =25590a(16) =28890a(17) =32390a(18) =36090a(19) =39990a(20) =44090a(21) =48390a(22) =52890a(23) =57590a(24) =62490a(25) =67590a(26) =72890a(27) =78390a(28) =84090a(29) =89990