Sequence shifts left three places under Weigh transform with a(n) = signum(n) for n<3.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =2a(8) =3a(9) =5a(10) =7a(11) =10a(12) =17a(13) =26a(14) =40a(15) =65a(16) =104a(17) =166a(18) =272a(19) =442a(20) =720a(21) =1186a(22) =1954a(23) =3222a(24) =5346a(25) =8881a(26) =14778a(27) =24668a(28) =41254a(29) =69088