A043987 - OEIS

%I #13 Jun 01 2024 17:59:59

%S 42,58,123,139,204,220,285,301,366,386,447,463,530,544,609,625,690,

%T 706,771,787,852,868,933,949,1014,1030,1095,1115,1176,1192,1259,1273,

%U 1338,1354,1419,1435,1500,1516,1581,1597,1662,1678

%N Numbers k such that 4 and 6 occur juxtaposed in the base-9 representation of k but not of k+1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{4,6}]>0 || SequenceCount[ IntegerDigits[ n,9],{6,4}]>0,1,0],{n,1700}],{1,0}] [[All, 1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 25 2017 *)

%Y Cf. A007095.

%K nonn,base

%O 1,1

%A _Clark Kimberling_