a(n) = 7*n^2 + 4*n + 1.

Terms

a(0) =4a(1) =1a(2) =12a(3) =37a(4) =76a(5) =129a(6) =196a(7) =277a(8) =372a(9) =481a(10) =604a(11) =741a(12) =892a(13) =1057a(14) =1236a(15) =1429a(16) =1636a(17) =1857a(18) =2092a(19) =2341a(20) =2604a(21) =2881a(22) =3172a(23) =3477a(24) =3796a(25) =4129a(26) =4476a(27) =4837a(28) =5212a(29) =5601