A043901 Numbers n such that 1 and 2 occur juxtaposed in the base 6 representation of n but not of n+1.

8, 13, 44, 53, 83, 85, 116, 121, 152, 157, 188, 193, 224, 229, 260, 269, 323, 332, 337, 368, 373, 404, 409, 440, 445, 503, 515, 517, 548, 553, 584, 589, 620, 625, 656, 661, 692, 701, 731, 733, 764, 769, 800, 805, 836, 841, 872