G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x)^4).

Terms

a(0) =1a(1) =1a(2) =0a(3) =-4a(4) =-6a(5) =28a(6) =119a(7) =-116a(8) =-1820a(9) =-2128a(10) =22212a(11) =79877a(12) =-172700a(13) =-1652728a(14) =-857428a(15) =25387284a(16) =71506309a(17) =-268817888a(18) =-1838702048a(19) =449975584a(20) =33164610276a(21) =68575577309a(22) =-429542625096