%I
%S 17,66,115,125,164,213,262,311,360,409,458,468,507,556,605,654,703,
%T 752,801,811,881,899,948,997,1046,1095,1144,1154,1193,1242,1291,1340,
%U 1389,1438,1487,1497,1536,1585,1634,1683,1732,1781
%N Numbers n such that string 2,3 occurs in the base 7 representation of n but not of n+1.
%t Select[Range[2000],MemberQ[Partition[IntegerDigits[#,7],2,1],{2,3}] && !MemberQ[ Partition[IntegerDigits[#+1,7],2,1],{2,3}]&] (* _Harvey P. Dale_, Feb 21 2013 *)
%K nonn,base
%O 1,1
%A _Clark Kimberling_
