G.f.: Sum_{n>=0} x^n * (x^n + i)^n / (1 + i*x^(n+1))^(n+1), where i^2 = -1.

Terms

a(0) =1a(1) =0a(2) =-1a(3) =2a(4) =2a(5) =0a(6) =-7a(7) =-2a(8) =8a(9) =0a(10) =8a(11) =12a(12) =-9a(13) =-28a(14) =-16a(15) =4a(16) =2a(17) =0a(18) =46a(19) =104a(20) =39a(21) =-100a(22) =-144a(23) =4a(24) =16a(25) =-144a(26) =-66a(27) =28a(28) =72a(29) =336