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

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =6a(6) =2a(7) =-20a(8) =-102a(9) =-312a(10) =-795a(11) =-1483a(12) =-1102a(13) =7035a(14) =51059a(15) =219453a(16) =779078a(17) =2307104a(18) =5508377a(19) =7633065a(20) =-19349069a(21) =-226127800a(22) =-1296826960a(23) =-5855601434a(24) =-22970901723a(25) =-78578482054a(26) =-224208769108a(27) =-429111559993a(28) =429212740026