A022338 Index of 5^n within sequence of numbers of form 3^i*5^j.

1, 3, 6, 11, 17, 25, 34, 45, 57, 71, 86, 103, 121, 141, 162, 184, 208, 233, 260, 288, 318, 349, 382, 416, 452, 489, 528, 568, 610, 653, 697, 743, 790, 839, 889, 941, 994, 1049, 1105, 1163, 1222, 1283, 1345, 1408, 1473, 1539, 1607, 1676, 1747, 1819, 1893, 1968