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%I #11 Nov 24 2022 15:53:47
%S 11,19,92,99,171,181,254,262,335,343,416,424,497,505,578,586,659,667,
%T 740,748,821,828,891,983,991,1064,1072,1145,1153,1226,1234,1307,1315,
%U 1388,1396,1469,1477,1539,1629,1639,1712,1720
%N Numbers k such that 1 and 2 occur juxtaposed in the base-9 representation of k but not of k-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{1,2}]>0 || SequenceCount[ IntegerDigits[n,9],{2,1}]>0,1,0],{n,2000}],{0,1}][[All,2]] (* _Harvey P. Dale_, Nov 24 2022 *)
%Y Cf. A007095.
%K nonn,base
%O 1,1
%A _Clark Kimberling_