A044058 Numbers n such that string 2,0 occurs in the base 3 representation of n but not of n-1.

6, 15, 18, 24, 33, 42, 45, 51, 54, 69, 72, 78, 87, 96, 99, 105, 114, 123, 126, 132, 135, 150, 153, 159, 162, 195, 204, 207, 213, 216, 231, 234, 240, 249, 258, 261, 267, 276, 285, 288, 294, 297, 312, 315, 321, 330, 339, 342, 348