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

Terms

a(0) =2a(1) =-2a(2) =1a(3) =2a(4) =2a(5) =1a(6) =2a(7) =10a(8) =26a(9) =44a(10) =68a(11) =149a(12) =398a(13) =938a(14) =1918a(15) =3916a(16) =8892a(17) =21258a(18) =49028a(19) =108580a(20) =242132a(21) =558456a(22) =1306824a(23) =3026445a(24) =6938518a(25) =15984346a(26) =37243510a(27) =87188492a(28) =203625452a(29) =474753470