a(n) = 15*n^2 - 9*n + 1.

Terms

a(0) =1a(1) =7a(2) =43a(3) =109a(4) =205a(5) =331a(6) =487a(7) =673a(8) =889a(9) =1135a(10) =1411a(11) =1717a(12) =2053a(13) =2419a(14) =2815a(15) =3241a(16) =3697a(17) =4183a(18) =4699a(19) =5245a(20) =5821a(21) =6427a(22) =7063a(23) =7729a(24) =8425a(25) =9151a(26) =9907a(27) =10693a(28) =11509a(29) =12355