a(n) = 6*n^2 + 4*n + 1.

Terms

a(0) =1a(1) =11a(2) =33a(3) =67a(4) =113a(5) =171a(6) =241a(7) =323a(8) =417a(9) =523a(10) =641a(11) =771a(12) =913a(13) =1067a(14) =1233a(15) =1411a(16) =1601a(17) =1803a(18) =2017a(19) =2243a(20) =2481a(21) =2731a(22) =2993a(23) =3267a(24) =3553a(25) =3851a(26) =4161a(27) =4483a(28) =4817a(29) =5163