%I #8 Aug 24 2021 06:29:49

%S 67,76,167,176,267,276,367,376,467,476,567,576,667,670,760,776,867,

%T 876,967,976,1067,1076,1167,1176,1267,1276,1367,1376,1467,1476,1567,

%U 1576,1667,1670,1760,1776,1867,1876,1967,1976,2067

%N Numbers k such that 6 and 7 occur juxtaposed in the base-10 representation of k but not of k-1.

%K nonn,base

%O 1,1

%A _Clark Kimberling_