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%I #11 Aug 23 2021 01:07:09
%S 15,55,96,135,177,217,258,298,339,379,420,460,495,541,582,622,663,703,
%T 744,784,825,864,906,946,987,1027,1068,1108,1149,1189,1215,1311,1351,
%U 1392,1432,1473,1513,1554,1593,1635,1675,1716
%N Numbers k such that 1 and 6 occur juxtaposed in the base-9 representation of k but not of k-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{1,6}]>0 || SequenceCount[IntegerDigits[n,9],{6,1}]>0,1,0],{n,2000}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 14 2019 *)
%Y Cf. A007095.
%K nonn,base
%O 1,1
%A _Clark Kimberling_