A031486 n-th number k which in base 7 has 2 fewer 0's than 6's.

48, 97, 146, 195, 244, 293, 307, 314, 321, 328, 335, 337, 338, 339, 340, 341, 440, 489, 538, 587, 636, 650, 657, 664, 671, 678, 680, 681, 682, 683, 684, 783, 832, 881, 930, 979, 993, 1000, 1007, 1014, 1021, 1023, 1024, 1025, 1026