A025718 Index of 6^n within sequence of numbers of form 6^i*9^j.

1, 2, 4, 7, 11, 16, 21, 27, 34, 42, 51, 60, 70, 81, 93, 106, 120, 134, 149, 165, 182, 200, 218, 237, 257, 278, 300, 323, 346, 370, 395, 421, 448, 475, 503, 532, 562, 593, 624, 656, 689, 723, 758, 794, 830, 867, 905, 944, 984, 1024, 1065, 1107, 1150, 1194, 1239, 1284