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%I #7 Jul 13 2019 13:49:48
%S 19,44,69,94,119,144,169,194,219,244,269,294,319,344,369,394,419,444,
%T 469,519,544,569,594,619,644,669,694,719,744,769,794,819,844,869,894,
%U 919,944,969,994,1019,1044,1069,1094,1144,1169
%N Numbers n such that string 3,4 occurs in the base 5 representation of n but not of n-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,5],{3,4}]>0,1,0],{n,1500}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 13 2019 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_