A029452 Numbers n such that n divides (right) concatenation of all numbers <= n written in base 7 (most significant digit on left).

1, 3, 7, 12, 21, 28, 44, 49, 60, 61, 63, 81, 84, 91, 97, 108, 140, 147, 180, 189, 196, 204, 212, 243, 252, 303, 308, 324, 343, 349, 376, 392, 441, 504, 831, 1029, 1057, 1176, 1561, 2401, 2744, 3101, 4312, 5096, 6027, 7203, 8232, 10339, 11669, 12936, 13755