%I #7 May 07 2022 19:31:24

%S 79,179,279,379,479,579,679,779,799,879,979,1079,1179,1279,1379,1479,

%T 1579,1679,1779,1799,1879,1979,2079,2179,2279,2379,2479,2579,2679,

%U 2779,2799,2879,2979,3079,3179,3279,3379,3479,3579

%N Numbers n such that string 7,9 occurs in the base 10 representation of n but not of n+1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{7,9}]>0,1,0],{n,3600}],{1,0}][[All,1]] (* _Harvey P. Dale_, May 07 2022 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_