%I #7 Oct 28 2020 13:14:00
%S 76,176,276,376,476,576,676,769,776,876,976,1076,1176,1276,1376,1476,
%T 1576,1676,1769,1776,1876,1976,2076,2176,2276,2376,2476,2576,2676,
%U 2769,2776,2876,2976,3076,3176,3276,3376,3476,3576
%N Numbers n such that string 7,6 occurs in the base 10 representation of n but not of n+1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n],{7,6}]>0,1,0],{n,4000}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Oct 28 2020 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_