%I #20 Apr 28 2021 02:43:28

%S 13,26,39,52,65,78,91,104,117,130,143,1872,1898,1911,1924,1937,1950,

%T 1963,1976,1989,2002,2015,3744,3757,3783,3796,3809,3822,3835,3848,

%U 3861,3874,3887,5616,5629,5642,5668,5681,5694,5707,5720,5733,5746,5759,7488,7501

%N Numbers each of whose runs of digits in base 12 has length 2.

%C 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

%C Numbers without repeating adjacent digits for which all digits are divisible by 13, in base 144. Consequently there are 11^n n-digit members of this sequence (base 144) and so (11^(n+1)-1)/10 members of this sequence below 144^n. - _Charles R Greathouse IV_, Feb 02 2014

%H Vincenzo Librandi, <a href="/A033010/b033010.txt">Table of n, a(n) for n = 1..1400</a>

%F a(n) = 13*A043316(n) (= 13*n for n < 12). - _M. F. Hasler_, Feb 02 2014

%t Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 12]]]=={2}&] (* _Vincenzo Librandi_, Feb 05 2014 *)

%o (Python)

%o from sympy.ntheory import digits

%o from itertools import groupby

%o def ok(n):

%o return all(len(list(g))==2 for k, g in groupby(digits(n, 12)[1:]))

%o print(list(filter(ok, range(1, 7502)))) # _Michael S. Branicky_, Apr 27 2021

%K nonn,base,easy

%O 1,1

%A _Clark Kimberling_