A046292 2^a(n) contains 2^6=64 as largest proper substring of form 2^n.

26, 31, 46, 59, 66, 67, 72, 77, 83, 86, 89, 92, 96, 101, 106, 111, 116, 119, 123, 124, 125, 126, 129, 131, 136, 138, 141, 142, 144, 148, 152, 153, 155, 157, 163, 165, 166, 171, 176, 177, 178, 181, 182, 183, 186, 193, 194, 197, 198, 199, 202, 204, 205, 206