"Sloping binary representation" of powers of 3 (A000244), slope = -1.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =3a(5) =9a(6) =11a(7) =17a(8) =19a(9) =25a(10) =123a(11) =65a(12) =195a(13) =169a(14) =171a(15) =753a(16) =435a(17) =249a(18) =2267a(19) =4065a(20) =8163a(21) =841a(22) =843a(23) =31313a(24) =29651a(25) =39769a(26) =38331a(27) =30081a(28) =160643a(29) =49769