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%I #7 Dec 29 2019 13:58:13
%S 13,38,63,65,88,113,138,163,188,190,213,238,263,288,313,315,325,363,
%T 388,413,438,440,463,488,513,538,563,565,588,613,638,663,688,690,713,
%U 738,763,788,813,815,838,863,888,913,938,940,950
%N Numbers n such that string 2,3 occurs in the base 5 representation of n but not of n-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,5],{2,3}]>0,1,0],{n,1000}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 29 2019 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_