a(n) = 74*n^2 - 1.

Terms

a(0) =73a(1) =295a(2) =665a(3) =1183a(4) =1849a(5) =2663a(6) =3625a(7) =4735a(8) =5993a(9) =7399a(10) =8953a(11) =10655a(12) =12505a(13) =14503a(14) =16649a(15) =18943a(16) =21385a(17) =23975a(18) =26713a(19) =29599a(20) =32633a(21) =35815a(22) =39145a(23) =42623a(24) =46249a(25) =50023a(26) =53945a(27) =58015a(28) =62233a(29) =66599