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%I #7 Apr 12 2024 09:17:18
%S 4,12,22,31,36,49,58,66,76,85,93,103,108,139,147,157,166,174,184,193,
%T 198,211,220,228,238,247,255,265,274,279,292,301,309,319,324,409,417,
%U 427,436,441,454,463,471,481,490,498,508,517
%N Numbers n such that string 1,1 occurs in the base 3 representation of n but not of n-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,3],{1,1}]>0,1,0],{n,600}],{0,1}][[;;,2]] (* _Harvey P. Dale_, Apr 12 2024 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_