a(n) = n*(3*n + 20).

Terms

a(0) =0a(1) =23a(2) =52a(3) =87a(4) =128a(5) =175a(6) =228a(7) =287a(8) =352a(9) =423a(10) =500a(11) =583a(12) =672a(13) =767a(14) =868a(15) =975a(16) =1088a(17) =1207a(18) =1332a(19) =1463a(20) =1600a(21) =1743a(22) =1892a(23) =2047a(24) =2208a(25) =2375a(26) =2548a(27) =2727a(28) =2912a(29) =3103