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

Terms

a(0) =1a(1) =-1a(2) =1a(3) =-3a(4) =5a(5) =-11a(6) =27a(7) =-69a(8) =187a(9) =-517a(10) =1461a(11) =-4163a(12) =11947a(13) =-34521a(14) =100261a(15) =-292835a(16) =859927a(17) =-2538141a(18) =7527545a(19) =-22422647a(20) =67055871a(21) =-201247141a(22) =605915529a(23) =-1829583727a(24) =5539081021a(25) =-16810214491a(26) =51130177087a(27) =-155839985097a(28) =475899781565