G.f. is Q_1(q) where q*Q_1(q^4) is a series quadrisection of the g.f. of A161800.

Terms

a(0) =2a(1) =-16a(2) =18a(3) =176a(4) =-544a(5) =-160a(6) =2834a(7) =-5104a(8) =3232a(9) =18032a(10) =-68992a(11) =48400a(12) =143074a(13) =-343088a(14) =461344a(15) =63888a(16) =-2298880a(17) =2963520a(18) =1387424a(19) =-5145536a(20) =10416514a(21) =-9297312a(22) =-31084704a(23) =42991712a(24) =34760672a(25) =-51170800a(26) =81567168a(27) =-94111088