%I #7 Sep 12 2018 18:25:23
%S 15,51,87,95,123,159,195,231,267,303,311,339,375,411,447,483,519,527,
%T 575,591,627,663,699,735,743,771,807,843,879,915,951,959,987,1023,
%U 1059,1095,1131,1167,1175,1203,1239,1275,1311,1347
%N Numbers n such that string 2,3 occurs in the base 6 representation of n but not of n+1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,6],{2,3}]>0,1,0],{n,1500}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Sep 12 2018 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_