G.f.: 1/(1 + x - x^2 - x^3 + x^4).

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-2a(4) =2a(5) =-1a(6) =-1a(7) =4a(8) =-8a(9) =12a(10) =-15a(11) =15a(12) =-10a(13) =-2a(14) =22a(15) =-49a(16) =79a(17) =-104a(18) =112a(19) =-88a(20) =17a(21) =111a(22) =-294a(23) =510a(24) =-710a(25) =815a(26) =-721a(27) =316a(28) =488a(29) =-1708