%I #7 Aug 31 2021 15:08:38
%S 63,163,263,363,463,563,639,663,763,863,963,1063,1163,1263,1363,1463,
%T 1563,1639,1663,1763,1863,1963,2063,2163,2263,2363,2463,2563,2639,
%U 2663,2763,2863,2963,3063,3163,3263,3363,3463,3563
%N Numbers n such that string 6,3 occurs in the base 10 representation of n but not of n+1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{6,3}]>0,1,0],{n,3600}],{1,0}][[All,1]] (* _Harvey P. Dale_, Aug 31 2021 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_