a(n) = (-1)^n * Fibonacci(2*n+1).

Terms

a(0) =1a(1) =-2a(2) =5a(3) =-13a(4) =34a(5) =-89a(6) =233a(7) =-610a(8) =1597a(9) =-4181a(10) =10946a(11) =-28657a(12) =75025a(13) =-196418a(14) =514229a(15) =-1346269a(16) =3524578a(17) =-9227465a(18) =24157817a(19) =-63245986a(20) =165580141a(21) =-433494437a(22) =1134903170a(23) =-2971215073a(24) =7778742049a(25) =-20365011074a(26) =53316291173a(27) =-139583862445a(28) =365435296162a(29) =-956722026041