a(n) = 9*n*(n+1).

Terms

a(0) =0a(1) =18a(2) =54a(3) =108a(4) =180a(5) =270a(6) =378a(7) =504a(8) =648a(9) =810a(10) =990a(11) =1188a(12) =1404a(13) =1638a(14) =1890a(15) =2160a(16) =2448a(17) =2754a(18) =3078a(19) =3420a(20) =3780a(21) =4158a(22) =4554a(23) =4968a(24) =5400a(25) =5850a(26) =6318a(27) =6804a(28) =7308a(29) =7830