G.f.: Sum_{n>=0} x^n * (1 + x^n)^n / (1 + x^(n+1))^(n+1).

Terms

a(0) =1a(1) =0a(2) =3a(3) =-2a(4) =2a(5) =0a(6) =9a(7) =-14a(8) =8a(9) =0a(10) =12a(11) =-12a(12) =15a(13) =-52a(14) =76a(15) =-36a(16) =2a(17) =0a(18) =50a(19) =-104a(20) =79a(21) =-140a(22) =324a(23) =-276a(24) =128a(25) =-144a(26) =118a(27) =-28a(28) =72a(29) =-336