A044362 Numbers n such that string 3,0 occurs in the base 10 representation of n but not of n-1.

30, 130, 230, 300, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1230, 1300, 1330, 1430, 1530, 1630, 1730, 1830, 1930, 2030, 2130, 2230, 2300, 2330, 2430, 2530, 2630, 2730, 2830, 2930, 3000, 3130, 3230, 3300, 3330, 3430