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 A033011 #16 Feb 05 2014 08:08:52
%S A033011 14,28,42,56,70,84,98,112,126,140,154,168,2366,2394,2408,2422,2436,
%T A033011 2450,2464,2478,2492,2506,2520,2534,4732,4746,4774,4788,4802,4816,
%U A033011 4830,4844,4858,4872,4886,4900,7098,7112,7126,7154
%N A033011 Every run of digits of n in base 13 has length 2.
%C A033011 See A043291 and A033001 through A033014 for the analog in other bases. See A033015 through A033029 for the variants with run lengths >= 2. - _M. F. Hasler_, Feb 02 2014
%H A033011 Vincenzo Librandi, <a href="/A033011/b033011.txt">Table of n, a(n) for n = 1..1800</a>
%F A033011 a(n) = 14*A043317(n) (= 14*n for n<13). - _M. F. Hasler_, Feb 02 2014
%t A033011 Select[Range[8000],Union[Length/@Split[IntegerDigits[#,13]]]=={2}&] (* _Harvey P. Dale_, Feb 27 2013 *)
%K A033011 nonn,base
%O A033011 1,1
%A A033011 _Clark Kimberling_