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Numbers n such that string 5,8 occurs in the base 9 representation of n but not of n-1.
0

%I #7 Apr 17 2019 18:55:19

%S 53,134,215,296,377,458,477,539,620,701,782,863,944,1025,1106,1187,

%T 1206,1268,1349,1430,1511,1592,1673,1754,1835,1916,1935,1997,2078,

%U 2159,2240,2321,2402,2483,2564,2645,2664,2726,2807

%N Numbers n such that string 5,8 occurs in the base 9 representation of n but not of n-1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{5,8}]>0,1,0],{n,3000}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 17 2019 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_