G.f. A(x) satisfies: 1 = Sum_{n=-oo..oo} (-x)^(n*(n+1)/2) * A(x)^(n*(n-1)/2), with A(0) = 0.

Terms

a(0) =1a(1) =0a(2) =0a(3) =2a(4) =0a(5) =0a(6) =8a(7) =0a(8) =0a(9) =44a(10) =0a(11) =6a(12) =280a(13) =0a(14) =96a(15) =1934a(16) =0a(17) =1124a(18) =14088a(19) =18a(20) =11792a(21) =106536a(22) =648a(23) =117626a(24) =828360a(25) =13416a(26) =1142288a(27) =6580780a(28) =216000a(29) =10921088