A024643 n written in fractional base 7/6.

0, 1, 2, 3, 4, 5, 6, 60, 61, 62, 63, 64, 65, 66, 650, 651, 652, 653, 654, 655, 656, 6540, 6541, 6542, 6543, 6544, 6545, 6546, 65430, 65431, 65432, 65433, 65434, 65435, 65436, 654320, 654321, 654322, 654323, 654324, 654325, 654326, 6543210, 6543211