a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ... + a(n-3)*a(3) for n >= 4, with initial terms 1, -1, 1, 1.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =1a(4) =0a(5) =0a(6) =2a(7) =3a(8) =1a(9) =2a(10) =11a(11) =17a(12) =12a(13) =25a(14) =81a(15) =127a(16) =134a(17) =276a(18) =696a(19) =1118a(20) =1492a(21) =3005a(22) =6607a(23) =10935a(24) =16766a(25) =33047a(26) =67249a(27) =114611a(28) =190706a(29) =369424