4-step Fibonacci sequence starting with 1,0,1,0.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =2a(5) =3a(6) =6a(7) =11a(8) =22a(9) =42a(10) =81a(11) =156a(12) =301a(13) =580a(14) =1118a(15) =2155a(16) =4154a(17) =8007a(18) =15434a(19) =29750a(20) =57345a(21) =110536a(22) =213065a(23) =410696a(24) =791642a(25) =1525939a(26) =2941342a(27) =5669619a(28) =10928542a(29) =21065442