First differences of A001468.

Terms

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