Moebius transform applied twice to sequence 1,0,0,0,....

Terms

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