A044381 - OEIS

%I #7 Dec 24 2023 15:56:14

%S 49,149,249,349,449,490,549,649,749,849,949,1049,1149,1249,1349,1449,

%T 1490,1549,1649,1749,1849,1949,2049,2149,2249,2349,2449,2490,2549,

%U 2649,2749,2849,2949,3049,3149,3249,3349,3449,3490

%N Numbers n such that string 4,9 occurs in the base 10 representation of n but not of n-1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{4,9}]>0,1,0],{n,3500}],{0,1}][[;;,2]] (* _Harvey P. Dale_, Dec 24 2023 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_