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%I #11 Aug 23 2021 01:07:22
%S 15,57,79,120,143,185,207,249,271,313,335,377,399,441,456,505,527,569,
%T 591,632,655,697,719,761,783,825,847,889,911,953,960,1039,1081,1103,
%U 1144,1167,1209,1231,1273,1295,1337,1359,1401
%N Numbers k such that 1 and 7 occur juxtaposed in the base-8 representation of k but not of k-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{1,7}]>0 || SequenceCount[IntegerDigits[n,8],{7,1}]>0,1,0],{n,1500}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Aug 26 2020 *)
%Y Cf. A007094.
%K nonn,base
%O 1,1
%A _Clark Kimberling_
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