a(n) = 216*n + 12.

Terms

a(0) =228a(1) =444a(2) =660a(3) =876a(4) =1092a(5) =1308a(6) =1524a(7) =1740a(8) =1956a(9) =2172a(10) =2388a(11) =2604a(12) =2820a(13) =3036a(14) =3252a(15) =3468a(16) =3684a(17) =3900a(18) =4116a(19) =4332a(20) =4548a(21) =4764a(22) =4980a(23) =5196a(24) =5412a(25) =5628a(26) =5844a(27) =6060a(28) =6276a(29) =6492