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%I #23 Aug 10 2021 14:54:01
%S 6,8,9,10,11,12,13,15,16,17,18,19,20,22,23,24,25,26,27,29,30,31,32,33,
%T 34,36,37,42,44,45,46,47,49,50,55,57,61,64,67,71,72,74,79,80,84,85,87,
%U 88,89,92,93,98,100,104,107,108,111,115,117
%N Numbers with exactly two distinct base-6 digits.
%H Robert Israel, <a href="/A031951/b031951.txt">Table of n, a(n) for n = 1..10000</a>
%H <a href="/index/Ar#6-automatic">Index entries for 6-automatic sequences</a>.
%p M:= 6: # get all terms < 6^M
%p sort([seq(seq(seq(seq(add(6^(m-j)*`if`(member(j,S2),d2,d1),j=1..m) ,
%p S2 = combinat:-powerset({$2..m}) minus {{}}),
%p d2 = {$0..5} minus {d1}), d1 = 1..5), m=2..M)]);# _Robert Israel_, Dec 03 2015
%t fQ[n_] := Length@ Union@ IntegerDigits[n, 6] == 2; Select[Range@117, fQ] (* _Robert G. Wilson v_, Dec 03 2015 *)
%Y Cf. A007092, A031948, A031949, A031950, A031952, A031953, A031954, A031955.
%K nonn,base,easy
%O 1,1
%A _Clark Kimberling_