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%I #8 Apr 04 2015 14:18:36
%S 0,1,2,3,4,5,7,8,9,10,11,13,14,15,16,17,19,20,21,22,23,26,27,28,29,35,
%T 36,38,39,40,41,42,44,45,46,47,48,51,52,53,54,55,57,58,59,65,66,67,69,
%U 70,71,72,73,76,77,78,79,80,82,83,84,85,86
%N Every string of 2 consecutive base 5 digits contains exactly 2 distinct numbers.
%F A031943 UNION {0}. [From _R. J. Mathar_, Oct 20 2008]
%t Select[Range[0,100],FreeQ[Differences[IntegerDigits[#,5]],0]&] (* _Harvey P. Dale_, Apr 04 2015 *)
%K nonn,base
%O 0,3
%A _Clark Kimberling_