Series reversion of A028310.

Terms

a(0) =1a(1) =-1a(2) =0a(3) =2a(4) =-2a(5) =-5a(6) =14a(7) =5a(8) =-72a(9) =68a(10) =278a(11) =-726a(12) =-520a(13) =4691a(14) =-3514a(15) =-21758a(16) =50374a(17) =56185a(18) =-374566a(19) =194596a(20) =1962618a(21) =-3956504a(22) =-6258320a(23) =33057877a(24) =-8974630a(25) =-190822072a(26) =330170022a(27) =710487590a(28) =-3088268200a(29) =18008739