288*n^2 - 168*n - 119.

Terms

a(0) =1a(1) =697a(2) =1969a(3) =3817a(4) =6241a(5) =9241a(6) =12817a(7) =16969a(8) =21697a(9) =27001a(10) =32881a(11) =39337a(12) =46369a(13) =53977a(14) =62161a(15) =70921a(16) =80257a(17) =90169a(18) =100657a(19) =111721a(20) =123361a(21) =135577a(22) =148369a(23) =161737a(24) =175681a(25) =190201a(26) =205297a(27) =220969a(28) =237217a(29) =254041