Period 2: repeat (2,4).

Terms

a(0) =2a(1) =4a(2) =2a(3) =4a(4) =2a(5) =4a(6) =2a(7) =4a(8) =2a(9) =4a(10) =2a(11) =4a(12) =2a(13) =4a(14) =2a(15) =4a(16) =2a(17) =4a(18) =2a(19) =4a(20) =2a(21) =4a(22) =2a(23) =4a(24) =2a(25) =4a(26) =2a(27) =4a(28) =2a(29) =4