A044657 - OEIS

%I #7 Jul 31 2019 12:48:14

%S 25,106,187,233,268,349,430,511,592,673,754,835,916,962,997,1078,1159,

%T 1240,1321,1402,1483,1564,1645,1691,1726,1807,1888,1969,2105,2131,

%U 2212,2293,2374,2420,2455,2536,2617,2698,2779,2860

%N Numbers n such that string 2,7 occurs in the base 9 representation of n but not of n+1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{2,7}]>0,1,0],{n,3000}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 31 2019 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_