a(n) = 2^(n-1)*Fibonacci(n-3), n >= 0.

Terms

a(0) =1a(1) =-1a(2) =2a(3) =0a(4) =8a(5) =16a(6) =64a(7) =192a(8) =640a(9) =2048a(10) =6656a(11) =21504a(12) =69632a(13) =225280a(14) =729088a(15) =2359296a(16) =7634944a(17) =24707072a(18) =79953920a(19) =258736128a(20) =837287936a(21) =2709520384a(22) =8768192512a(23) =28374466560a(24) =91821703168a(25) =297141272576a(26) =961569357824