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

Terms

a(0) =1a(1) =0a(2) =-1a(3) =2a(4) =0a(5) =-11a(6) =28a(7) =1a(8) =-206a(9) =564a(10) =38a(11) =-4711a(12) =13329a(13) =1273a(14) =-119762a(15) =344707a(16) =41884a(17) =-3251250a(18) =9445976a(19) =1381154a(20) =-92305098a(21) =269504686a(22) =45848871a(23) =-2707126108a(24) =7921304973a(25) =1532928960a(26) =-81375728566a(27) =238196143730a(28) =51591751698