A043398 Numbers n such that number of 1's in base 7 is 2.

8, 50, 56, 58, 59, 60, 61, 62, 64, 71, 78, 85, 92, 106, 155, 204, 253, 302, 344, 350, 352, 353, 354, 355, 356, 358, 365, 372, 379, 386, 392, 394, 395, 396, 397, 398, 406, 408, 409, 410, 411, 412, 413, 415, 416, 417, 418, 419, 420