A044765 Numbers n such that string 5,2 occurs in the base 10 representation of n but not of n+1.

52, 152, 252, 352, 452, 529, 552, 652, 752, 852, 952, 1052, 1152, 1252, 1352, 1452, 1529, 1552, 1652, 1752, 1852, 1952, 2052, 2152, 2252, 2352, 2452, 2529, 2552, 2652, 2752, 2852, 2952, 3052, 3152, 3252, 3352, 3452, 3529