This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A008558 #18 Sep 11 2021 10:47:11 %S A008558 9,11,13,15,17,21,25,31,37,45,55,67,103,147,223,337,521,1011,1763, %T A008558 3343,6417,14421,34125,102515,310163,1135623,4252007,20160547, %U A008558 114720043,665476453,4752456545,43321135541,502611010665,7240574662151,151272370273007 %N A008558 Repeatedly convert from decimal to octal. %t A008558 NestList[FromDigits[IntegerDigits[#,8]]&,9,40] (* _Harvey P. Dale_, Apr 09 2012 *) %o A008558 (Python) %o A008558 def aupton(terms): %o A008558 alst = [9] %o A008558 for n in range(2, terms+1): alst.append(int(oct(alst[-1])[2:])) %o A008558 return alst %o A008558 print(aupton(35)) # _Michael S. Branicky_, Sep 11 2021 %Y A008558 Cf. A007094. %K A008558 nonn,base %O A008558 1,1 %A A008558 sbv(AT)VNET.IBM.COM (Scott Vetter), msvetter(AT)eng.xyplex.com (Mark Vetter)