A044076 Numbers n such that string 3,3 occurs in the base 4 representation of n but not of n-1.

15, 31, 47, 60, 79, 95, 111, 124, 143, 159, 175, 188, 207, 223, 239, 271, 287, 303, 316, 335, 351, 367, 380, 399, 415, 431, 444, 463, 479, 495, 527, 543, 559, 572, 591, 607, 623, 636, 655, 671, 687, 700, 719, 735, 751, 783, 799