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%I #7 Jan 13 2019 15:47:09
%S 59,159,259,359,459,559,599,659,759,859,959,1059,1159,1259,1359,1459,
%T 1559,1599,1659,1759,1859,1959,2059,2159,2259,2359,2459,2559,2599,
%U 2659,2759,2859,2959,3059,3159,3259,3359,3459,3559
%N Numbers n such that string 5,9 occurs in the base 10 representation of n but not of n+1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{5,9}]>0,1,0],{n,4000}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 13 2019 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_