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

Terms

a(0) =99a(1) =398a(2) =897a(3) =1596a(4) =2495a(5) =3594a(6) =4893a(7) =6392a(8) =8091a(9) =9990a(10) =12089a(11) =14388a(12) =16887a(13) =19586a(14) =22485a(15) =25584a(16) =28883a(17) =32382a(18) =36081a(19) =39980a(20) =44079a(21) =48378a(22) =52877a(23) =57576a(24) =62475a(25) =67574a(26) =72873a(27) =78372a(28) =84071a(29) =89970