G.f.: Product_{k>0} (1-x^(4k-1)) / (1-x^(4k-2)).

Terms

a(0) =1a(1) =0a(2) =1a(3) =-1a(4) =1a(5) =-1a(6) =2a(7) =-2a(8) =2a(9) =-3a(10) =4a(11) =-4a(12) =5a(13) =-6a(14) =7a(15) =-8a(16) =9a(17) =-11a(18) =13a(19) =-14a(20) =17a(21) =-20a(22) =22a(23) =-25a(24) =29a(25) =-33a(26) =37a(27) =-42a(28) =48a(29) =-54