a(n)=-4a(n-4).

Terms

a(0) =0a(1) =2a(2) =3a(3) =1a(4) =0a(5) =-8a(6) =-12a(7) =-4a(8) =0a(9) =32a(10) =48a(11) =16a(12) =0a(13) =-128a(14) =-192a(15) =-64a(16) =0a(17) =512a(18) =768a(19) =256a(20) =0a(21) =-2048a(22) =-3072a(23) =-1024a(24) =0a(25) =8192a(26) =12288a(27) =4096a(28) =0a(29) =-32768