a(n) = Fibonacci(n) - 2^(floor(n/2)).

Terms

a(0) =-1a(1) =0a(2) =-1a(3) =0a(4) =-1a(5) =1a(6) =0a(7) =5a(8) =5a(9) =18a(10) =23a(11) =57a(12) =80a(13) =169a(14) =249a(15) =482a(16) =731a(17) =1341a(18) =2072a(19) =3669a(20) =5741a(21) =9922a(22) =15663a(23) =26609a(24) =42272a(25) =70929a(26) =113201a(27) =188226a(28) =301427a(29) =497845