%I #8 Aug 23 2021 21:46:11
%S 27,72,127,172,227,270,327,372,427,472,527,572,627,672,720,772,827,
%T 872,927,972,1027,1072,1127,1172,1227,1270,1327,1372,1427,1472,1527,
%U 1572,1627,1672,1720,1772,1827,1872,1927,1972,2027
%N Numbers k such that 2 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_