A044020 - OEIS

%I #11 Aug 29 2021 01:55:01

%S 34,43,134,143,234,243,334,349,439,443,534,543,634,643,734,743,834,

%T 843,934,943,1034,1043,1134,1143,1234,1243,1334,1349,1439,1443,1534,

%U 1543,1634,1643,1734,1743,1834,1843,1934,1943,2034

%N Numbers k such that 3 and 4 occur juxtaposed in the base-10 representation of k but not of k+1.

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{3,4}]>0 || SequenceCount[ IntegerDigits[n],{4,3}]>0,1,0],{n,2500}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 09 2017 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_