%I

%S 12,112,129,212,312,412,512,612,712,812,912,1012,1112,1129,1299,1312,

%T 1412,1512,1612,1712,1812,1912,2012,2112,2129,2212,2312,2412,2512,

%U 2612,2712,2812,2912,3012,3112,3129,3212,3312,3412

%N Numbers n such that string 1,2 occurs in the base 10 representation of n but not of n+1.

%K nonn,base

%O 1,1

%A _Clark Kimberling_