G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x))^3.

Terms

a(0) =1a(1) =1a(2) =-2a(3) =-2a(4) =15a(5) =-4a(6) =-122a(7) =204a(8) =903a(9) =-3374a(10) =-4635a(11) =43539a(12) =-13233a(13) =-475123a(14) =873392a(15) =4244591a(16) =-16906773a(17) =-24952174a(18) =244162840a(19) =-74520792a(20) =-2901715074a(21) =5483226036a(22) =27740164293a(23) =-112969486284a(24) =-172903931727a(26) =-513739179725