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%I #7 Jun 09 2022 19:25:50
%S 19,119,190,219,319,419,519,619,719,819,919,1019,1119,1190,1219,1319,
%T 1419,1519,1619,1719,1819,1900,2019,2119,2190,2219,2319,2419,2519,
%U 2619,2719,2819,2919,3019,3119,3190,3219,3319,3419
%N Numbers n such that string 1,9 occurs in the base 10 representation of n but not of n-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{1,9}]>0,1,0],{n,3500}],{0,1}][[All,2]] (* _Harvey P. Dale_, Jun 09 2022 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_