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

Terms

a(0) =1a(1) =1a(2) =-1a(3) =-3a(4) =4a(5) =12a(6) =-38a(7) =-33a(8) =428a(9) =-696a(10) =-3640a(11) =23140a(12) =-24766a(13) =-358024a(14) =2254416a(15) =-2636188a(16) =-48229769a(17) =372329934a(18) =-777177980a(19) =-8375653981a(20) =92394060425a(21) =-351172999190