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 A033012 #14 Feb 05 2014 03:14:48
%S A033012 15,30,45,60,75,90,105,120,135,150,165,180,195,2940,2970,2985,3000,
%T A033012 3015,3030,3045,3060,3075,3090,3105,3120,3135,5880,5895,5925,5940,
%U A033012 5955,5970,5985,6000,6015,6030,6045,6060,6075,8820
%N A033012 Every run of digits of n in base 14 has length 2.
%C A033012 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 04 2014
%H A033012 Vincenzo Librandi, <a href="/A033012/b033012.txt">Table of n, a(n) for n = 1..2000</a>
%F A033012 a(n) = 15*A043318(n) (= 15*n for n<14). - _M. F. Hasler_, Feb 02 2014
%t A033012 Select[Range[9000],Union[Length/@Split[IntegerDigits[#,14]]]=={2}&] (* _Harvey P. Dale_, Apr 26 2013 *)
%K A033012 nonn,base
%O A033012 1,1
%A A033012 _Clark Kimberling_