[3->null]-transform of three-symbol Thue-Morse A026600.

Terms

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