A044454 Numbers n such that string 3,0 occurs in the base 4 representation of n but not of n+1.

12, 28, 44, 51, 60, 76, 92, 108, 115, 124, 140, 156, 172, 179, 188, 207, 220, 236, 243, 252, 268, 284, 300, 307, 316, 332, 348, 364, 371, 380, 396, 412, 428, 435, 444, 463, 476, 492, 499, 508, 524, 540, 556, 563, 572, 588, 604