A121701 Lexicographically smallest sequence such that a(m)<>a(n) for all m with m<>n except either for m=2*n or n=2*m.

1, 1, 2, 3, 4, 2, 5, 3, 6, 4, 7, 8, 9, 5, 10, 11, 12, 6, 13, 14, 15, 7, 16, 8, 17, 9, 18, 19, 20, 10, 21, 11, 22, 12, 23, 24, 25, 13, 26, 14, 27, 15, 28, 29, 30, 16, 31, 32, 33, 17, 34, 35, 36, 18, 37, 19, 38, 20, 39, 40, 41, 21, 42, 43, 44, 22, 45, 46, 47, 23, 48, 24, 49, 25, 50