Erroneous version of A003406.

Terms

a(0) =1a(1) =1a(2) =-2a(3) =2a(4) =-2a(5) =1a(6) =0a(7) =1a(8) =-2a(9) =0a(10) =2a(11) =0a(12) =-1a(13) =-2a(14) =2a(15) =1a(16) =0a(17) =-2a(18) =2a(19) =-2