a(n) = [x^n] Product_{k>=1} ((1 - x^k)*(1 - x^(2*k)))^n.

Terms

a(0) =1a(1) =-1a(2) =-3a(3) =14a(4) =-11a(5) =-81a(6) =282a(7) =-57a(8) =-2043a(9) =5405a(10) =2417a(11) =-46476a(12) =94522a(13) =110512a(14) =-943407a(15) =1505289a(16) =2807589a(17) =-16888311a(18) =23645199a(19) =46006542a(20) =-265972791a(21) =472882620a(22) =187884672a(23) =-3981273597a(24) =14234579226a(25) =-19187383356a(26) =-78662039004a(27) =502118911904a(28) =-847583768679