a(n) = 8*n^2 - 6*n - 1.

Terms

a(0) =1a(1) =19a(2) =53a(3) =103a(4) =169a(5) =251a(6) =349a(7) =463a(8) =593a(9) =739a(10) =901a(11) =1079a(12) =1273a(13) =1483a(14) =1709a(15) =1951a(16) =2209a(17) =2483a(18) =2773a(19) =3079a(20) =3401a(21) =3739a(22) =4093a(23) =4463a(24) =4849a(25) =5251a(26) =5669a(27) =6103a(28) =6553a(29) =7019