A044271 - OEIS

%I #7 Dec 29 2018 15:59:01

%S 20,101,180,263,344,425,506,587,668,749,830,909,992,1073,1154,1235,

%T 1316,1397,1478,1559,1620,1721,1802,1883,1964,2045,2126,2207,2288,

%U 2367,2450,2531,2612,2693,2774,2855,2936,3017,3096

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

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{2,2}]>0,1,0],{n,4000}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 29 2018 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_