A044623 Numbers n such that string 6,7 occurs in the base 8 representation of n but not of n+1.

55, 119, 183, 247, 311, 375, 447, 503, 567, 631, 695, 759, 823, 887, 959, 1015, 1079, 1143, 1207, 1271, 1335, 1399, 1471, 1527, 1591, 1655, 1719, 1783, 1847, 1911, 1983, 2039, 2103, 2167, 2231, 2295, 2359, 2423, 2495, 2551