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Numbers k such that 2 and 4 occur juxtaposed in the base-8 representation of k but not of k-1.
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%I #11 Sep 07 2021 16:29:21

%S 20,34,84,98,148,160,212,226,272,290,340,354,404,418,468,482,532,546,

%T 596,610,660,672,724,738,784,802,852,866,916,930,980,994,1044,1058,

%U 1108,1122,1172,1184,1236,1250,1280,1364,1378,1428

%N Numbers k such that 2 and 4 occur juxtaposed in the base-8 representation of k but not of k-1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{2,4}]>0 || SequenceCount[ IntegerDigits[n,8],{4,2}]>0,1,0],{n,1500}],{0,1}][[All,2]] (* _Harvey P. Dale_, Sep 07 2021 *)

%Y Cf. A007094.

%K nonn,base

%O 1,1

%A _Clark Kimberling_