A037977 Numbers whose maximal base 4 run length is 2.

5, 10, 15, 16, 20, 22, 23, 26, 31, 32, 37, 40, 41, 43, 47, 48, 53, 58, 60, 61, 62, 65, 66, 67, 69, 74, 79, 80, 81, 82, 83, 88, 89, 90, 91, 92, 93, 94, 95, 96, 101, 104, 105, 107, 111, 112