a(n) = 121*n^2 - n.

Terms

a(0) =120a(1) =482a(2) =1086a(3) =1932a(4) =3020a(5) =4350a(6) =5922a(7) =7736a(8) =9792a(9) =12090a(10) =14630a(11) =17412a(12) =20436a(13) =23702a(14) =27210a(15) =30960a(16) =34952a(17) =39186a(18) =43662a(19) =48380a(20) =53340a(21) =58542a(22) =63986a(23) =69672a(24) =75600a(25) =81770a(26) =88182a(27) =94836a(28) =101732a(29) =108870