A081609 Number of numbers <= n having at least one 1 in their ternary representation.

0, 1, 1, 2, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 14, 15, 15, 16, 17, 18, 18, 19, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 46, 47, 47, 48, 49, 50, 50, 51, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 60, 61