a(n) = n*(n+3).

Terms

a(0) =0a(1) =4a(2) =10a(3) =18a(4) =28a(5) =40a(6) =54a(7) =70a(8) =88a(9) =108a(10) =130a(11) =154a(12) =180a(13) =208a(14) =238a(15) =270a(16) =304a(17) =340a(18) =378a(19) =418a(20) =460a(21) =504a(22) =550a(23) =598a(24) =648a(25) =700a(26) =754a(27) =810a(28) =868a(29) =928