A044141 Numbers n such that string 0,3 occurs in the base 7 representation of n but not of n-1.

52, 101, 150, 199, 248, 297, 346, 364, 395, 444, 493, 542, 591, 640, 689, 707, 738, 787, 836, 885, 934, 983, 1032, 1050, 1081, 1130, 1179, 1228, 1277, 1326, 1375, 1393, 1424, 1473, 1522, 1571, 1620, 1669, 1718, 1736, 1767, 1816