A044562 Numbers n such that string 6,1 occurs in the base 7 representation of n but not of n+1.

43, 92, 141, 190, 239, 288, 307, 337, 386, 435, 484, 533, 582, 631, 650, 680, 729, 778, 827, 876, 925, 974, 993, 1023, 1072, 1121, 1170, 1219, 1268, 1317, 1336, 1366, 1415, 1464, 1513, 1562, 1611, 1660, 1679, 1709, 1758, 1807