Repeatedly convert from decimal to octal.

Terms

a(0) =9a(1) =11a(2) =13a(3) =15a(4) =17a(5) =21a(6) =25a(7) =31a(8) =37a(9) =45a(10) =55a(11) =67a(12) =103a(13) =147a(14) =223a(15) =337a(16) =521a(17) =1011a(18) =1763a(19) =3343a(20) =6417a(21) =14421a(22) =34125a(23) =102515a(24) =310163a(25) =1135623a(26) =4252007a(27) =20160547a(28) =114720043a(29) =665476453