A025639 Exponent of 2 (value of i) in n-th number of form 2^i*10^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, 13, 0, 10, 7, 4, 14, 1, 11, 8, 5, 15, 2, 12, 9, 6, 16, 3, 13, 0, 10, 7, 17, 4, 14, 1, 11, 8, 18, 5, 15, 2, 12, 9, 19, 6, 16, 3, 13, 0, 10, 20, 7, 17, 4, 14, 1, 11, 21, 8, 18, 5, 15, 2, 12, 22, 9, 19