A variation on A056223.

Terms

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