%I #14 Jun 11 2022 09:38:24
%S 30,103,130,203,230,309,330,403,430,503,530,603,630,703,730,803,830,
%T 903,930,1003,1039,1103,1130,1203,1230,1309,1330,1403,1430,1503,1530,
%U 1603,1630,1703,1730,1803,1830,1903,1930,2003,2039
%N Numbers k such that 0 and 3 occur juxtaposed in the base-10 representation of k but not of k+1.
%H Michael De Vlieger, <a href="/A043998/b043998.txt">Table of n, a(n) for n = 1..10000</a>
%t With[{j = 0, k = 3}, Position[Partition[Array[Boole[Total@ {SequenceCount[#, {j, k}], SequenceCount[#, {k, j}]} > 0] &@ IntegerDigits[#] &, 2100], 2, 1], {1, 0}][[All, 1]]] (* _Michael De Vlieger_, Aug 27 2021 *)
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{0,3}]>0||SequenceCount[ IntegerDigits[ n],{3,0}]>0,1,0],{n,2100}],{1,0}][[All,1]] (* _Harvey P. Dale_, Jun 11 2022 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_