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 A033006 #11 Feb 05 2014 08:09:44
%S A033006 9,18,27,36,45,54,63,576,594,603,612,621,630,639,1152,1161,1179,1188,
%T A033006 1197,1206,1215,1728,1737,1746,1764,1773,1782,1791,2304,2313,2322,
%U A033006 2331,2349,2358,2367,2880,2889,2898,2907,2916,2934
%N A033006 Every run of digits of n in base 8 has length 2.
%C A033006 See A043291 and A033001 through A033014 for the analog in other bases, A033015 - A033029 for the variants with run lengths >= 2. - _M. F. Hasler_, Feb 02 2014
%H A033006 Vincenzo Librandi, <a href="/A033006/b033006.txt">Table of n, a(n) for n = 1..1400</a>
%F A033006 a(n) = 9*A043312(n) (= 9*n for n<8). - _M. F. Hasler_, Feb 02 2014
%t A033006 Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 8]]]=={2}&] (* _Vincenzo Librandi_, Feb 05 2014 *)
%K A033006 nonn,base
%O A033006 1,1
%A A033006 _Clark Kimberling_
%E A033006 Typo in name corrected by _Vincenzo Librandi_, Feb 05 2014