A024637 n written in fractional base 6/4.

0, 1, 2, 3, 4, 5, 40, 41, 42, 43, 44, 45, 420, 421, 422, 423, 424, 425, 4200, 4201, 4202, 4203, 4204, 4205, 4240, 4241, 4242, 4243, 4244, 4245, 42020, 42021, 42022, 42023, 42024, 42025, 42400, 42401, 42402, 42403, 42404, 42405, 42440, 42441, 42442, 42443