G.f. satisfies: A(x) = 1 + x*A(x)/A(-x) + x^2*A(x)*A(-x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =2a(4) =5a(5) =-2a(6) =3a(7) =-20a(8) =-2a(9) =-38a(10) =75a(11) =84a(12) =612a(13) =596a(14) =2293a(15) =534a(16) =4722a(17) =-6354a(18) =6716a(19) =-27696a(20) =44962a(21) =-8232a(22) =391279a(23) =310072a(24) =1975046a(25) =906028a(26) =6363470a(27) =-2135522a(28) =15639296a(29) =-21729494