A025701 Index of 4^n within sequence of numbers of form 3^i*4^j.

1, 3, 6, 10, 16, 23, 31, 40, 51, 63, 76, 90, 106, 123, 141, 160, 181, 203, 226, 250, 276, 303, 331, 361, 392, 424, 457, 492, 528, 565, 603, 643, 684, 726, 769, 814, 860, 907, 955, 1005, 1056, 1108, 1161, 1216, 1272, 1329, 1388, 1448, 1509, 1571, 1635, 1700, 1766