A043480 Numbers n such that number of 6's in base 9 is 4.

4920, 11481, 18042, 24603, 31164, 37725, 39912, 40641, 41370, 42099, 42828, 43557, 43800, 43881, 43962, 44043, 44124, 44205, 44232, 44241, 44250, 44259, 44268, 44277, 44280, 44281, 44282, 44283, 44284, 44285, 44287