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

Terms

a(0) =13a(1) =74a(2) =219a(3) =484a(4) =905a(5) =1518a(6) =2359a(7) =3464a(8) =4869a(9) =6610a(10) =8723a(11) =11244a(12) =14209a(13) =17654a(14) =21615a(15) =26128a(16) =31229a(17) =36954a(18) =43339a(19) =50420a(20) =58233a(21) =66814a(22) =76199a(23) =86424a(24) =97525a(25) =109538a(26) =122499a(27) =136444a(28) =151409a(29) =167430