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

Terms

a(0) =1a(1) =3a(2) =2a(3) =8a(4) =-9a(5) =62a(6) =-230a(7) =1054a(8) =-4753a(9) =22208a(10) =-105419a(11) =508396a(12) =-2482284a(13) =12248430a(14) =-60980860a(15) =305955372a(16) =-1545397447a(17) =7852100312a(18) =-40105277621a(19) =205798130624