A044740 Numbers n such that string 2,7 occurs in the base 10 representation of n but not of n+1.

27, 127, 227, 279, 327, 427, 527, 627, 727, 827, 927, 1027, 1127, 1227, 1279, 1327, 1427, 1527, 1627, 1727, 1827, 1927, 2027, 2127, 2227, 2279, 2327, 2427, 2527, 2627, 2799, 2827, 2927, 3027, 3127, 3227, 3279, 3327, 3427