%I #7 Nov 24 2021 13:27:49

%S 33,82,131,180,229,237,278,327,376,425,474,523,572,580,621,670,719,

%T 768,817,866,915,923,964,1013,1062,1111,1160,1209,1258,1266,1307,1356,

%U 1405,1454,1503,1552,1601,1609,1665,1699,1748,1797

%N Numbers n such that string 4,5 occurs in the base 7 representation of n but not of n+1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,7],{4,5}]>0,1,0],{n,2000}],{1,0}][[All,1]] (* _Harvey P. Dale_, Nov 24 2021 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_