A044074 Numbers n such that string 3,1 occurs in the base 4 representation of n but not of n-1.

13, 29, 45, 52, 61, 77, 93, 109, 116, 125, 141, 157, 173, 180, 189, 205, 208, 237, 244, 253, 269, 285, 301, 308, 317, 333, 349, 365, 372, 381, 397, 413, 429, 436, 445, 461, 464, 493, 500, 509, 525, 541, 557, 564, 573, 589, 605