%I #7 Dec 09 2018 13:58:49
%S 44,144,244,344,449,544,644,744,844,944,1044,1144,1244,1344,1449,1544,
%T 1644,1744,1844,1944,2044,2144,2244,2344,2449,2544,2644,2744,2844,
%U 2944,3044,3144,3244,3344,3449,3544,3644,3744,3844
%N Numbers n such that string 4,4 occurs in the base 10 representation of n but not of n+1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{4,4}]>0,1,0],{n,4000}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 09 2018 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_