a(n) = 2*n*(7*n + 5).

Terms

a(0) =0a(1) =24a(2) =76a(3) =156a(4) =264a(5) =400a(6) =564a(7) =756a(8) =976a(9) =1224a(10) =1500a(11) =1804a(12) =2136a(13) =2496a(14) =2884a(15) =3300a(16) =3744a(17) =4216a(18) =4716a(19) =5244a(20) =5800a(21) =6384a(22) =6996a(23) =7636a(24) =8304a(25) =9000a(26) =9724a(27) =10476a(28) =11256a(29) =12064