A043234 - OEIS

%I #10 Sep 15 2024 15:30:12

%S 24,42,124,142,224,240,324,342,420,442,524,542,624,642,724,742,824,

%T 842,924,942,1024,1042,1124,1142,1224,1240,1324,1342,1420,1442,1524,

%U 1542,1624,1642,1724,1742,1824,1842,1924,1942,2024

%N Numbers k such that 2 and 4 occur juxtaposed in the base-10 representation of k but not of k-1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{2,4}]>0||SequenceCount[ IntegerDigits[ n],{4,2}]>0,1,0],{n,2500}],{0,1}][[;;,2]] (* _Harvey P. Dale_, Sep 15 2024 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_