A043133 Numbers n such that 0 and 3 occur juxtaposed in the base 7 representation of n but not of n-1.

21, 52, 70, 101, 119, 147, 168, 199, 217, 248, 266, 297, 315, 346, 364, 395, 413, 444, 462, 490, 511, 542, 560, 591, 609, 640, 658, 689, 707, 738, 756, 787, 805, 833, 854, 885, 903, 934, 952, 983, 1001, 1029, 1081, 1099, 1130