A025638 Exponent of 2 (value of i) in n-th number of form 2^i*9^j.

0, 1, 2, 3, 0, 4, 1, 5, 2, 6, 3, 0, 7, 4, 1, 8, 5, 2, 9, 6, 3, 0, 10, 7, 4, 1, 11, 8, 5, 2, 12, 9, 6, 3, 0, 13, 10, 7, 4, 1, 14, 11, 8, 5, 2, 15, 12, 9, 6, 3, 0, 16, 13, 10, 7, 4, 1, 17, 14, 11, 8, 5, 2, 18, 15, 12, 9, 6, 3, 19, 0, 16, 13, 10, 7, 4, 20, 1, 17, 14, 11, 8, 5, 21, 2, 18, 15, 12, 9, 6, 22