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

Terms

a(0) =1a(1) =-1a(2) =1a(3) =3a(4) =4a(5) =3a(6) =4a(7) =19a(8) =60a(9) =124a(10) =214a(11) =455a(12) =1266a(13) =3404a(14) =7974a(15) =17699a(16) =42050a(17) =107956a(18) =276534a(19) =680140a(20) =1647872a(21) =4082562a(22) =10366604a(23) =26363583a(24) =66318590a(25) =166265630a(26) =420151570a(27) =1070885100a(28) =2734066540a(29) =6964626146