A043234 Numbers n such that 2 and 4 occur juxtaposed in the base 10 representation of n but not of n-1.

24, 42, 124, 142, 224, 240, 324, 342, 420, 442, 524, 542, 624, 642, 724, 742, 824, 842, 924, 942, 1024, 1042, 1124, 1142, 1224, 1240, 1324, 1342, 1420, 1442, 1524, 1542, 1624, 1642, 1724, 1742, 1824, 1842, 1924, 1942, 2024