A039005 Numbers n such that representation in base 4 has same number of 1's and 3's.

0, 2, 7, 8, 10, 13, 19, 27, 28, 30, 32, 34, 39, 40, 42, 45, 49, 52, 54, 57, 67, 75, 76, 78, 95, 99, 107, 108, 110, 112, 114, 119, 120, 122, 125, 128, 130, 135, 136, 138, 141, 147, 155, 156, 158, 160, 162, 167, 168, 170, 173, 177, 180, 182, 185, 193, 196, 198