A008558 - OEIS

%I #18 Sep 11 2021 10:47:11

%S 9,11,13,15,17,21,25,31,37,45,55,67,103,147,223,337,521,1011,1763,

%T 3343,6417,14421,34125,102515,310163,1135623,4252007,20160547,

%U 114720043,665476453,4752456545,43321135541,502611010665,7240574662151,151272370273007

%N Repeatedly convert from decimal to octal.

%t NestList[FromDigits[IntegerDigits[#,8]]&,9,40] (* _Harvey P. Dale_, Apr 09 2012 *)

%o (Python)

%o def aupton(terms):

%o     alst = [9]

%o     for n in range(2, terms+1): alst.append(int(oct(alst[-1])[2:]))

%o     return alst

%o print(aupton(35)) # _Michael S. Branicky_, Sep 11 2021

%Y Cf. A007094.

%K nonn,base

%O 1,1

%A sbv(AT)VNET.IBM.COM (Scott Vetter), msvetter(AT)eng.xyplex.com (Mark Vetter)