a(n) = 16*n^2 - 2*n.

Terms

a(0) =14a(1) =60a(2) =138a(3) =248a(4) =390a(5) =564a(6) =770a(7) =1008a(8) =1278a(9) =1580a(10) =1914a(11) =2280a(12) =2678a(13) =3108a(14) =3570a(15) =4064a(16) =4590a(17) =5148a(18) =5738a(19) =6360a(20) =7014a(21) =7700a(22) =8418a(23) =9168a(24) =9950a(25) =10764a(26) =11610a(27) =12488a(28) =13398a(29) =14340