A004287 Least positive multiple of n written in base 7 using only 0 and 1.

1, 11, 111, 11, 101, 111111, 10, 11, 1011, 101, 10011, 111111, 1011, 110, 11001, 1111, 100111, 1101111, 111, 1111, 1110, 11101, 101011, 111111, 101, 111001, 1011, 110, 1111111, 1011111, 100111, 11011, 10011, 100111, 1010, 1101111