A044491 Numbers n such that string 1,2 occurs in the base 6 representation of n but not of n+1.

8, 44, 53, 80, 116, 152, 188, 224, 260, 269, 323, 332, 368, 404, 440, 476, 485, 512, 548, 584, 620, 656, 692, 701, 728, 764, 800, 836, 872, 908, 917, 944, 980, 1016, 1052, 1088, 1124, 1133, 1160, 1196, 1232, 1268, 1304, 1340, 1349