G.f. satisfies A(x) = exp( Sum_{k>=1} ((-2)^k + A(x^k)) * x^k/k ).

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-2a(4) =4a(5) =-6a(6) =13a(7) =-20a(8) =38a(9) =-65a(10) =129a(11) =-228a(12) =435a(13) =-794a(14) =1528a(15) =-2833a(16) =5421a(17) =-10189a(18) =19561a(19) =-37091a(20) =71247a(21) =-135973a(22) =261879a(23) =-502303a(24) =969181a(25) =-1866210a(26) =3608664a(27) =-6970576a(28) =13504298a(29) =-26152744