A043141 Numbers n such that 1 and 6 occur juxtaposed in the base 7 representation of n but not of n-1.

13, 43, 62, 91, 111, 141, 160, 190, 209, 239, 258, 288, 301, 337, 356, 386, 405, 434, 454, 484, 503, 533, 552, 582, 601, 631, 637, 699, 729, 748, 777, 797, 827, 846, 876, 895, 925, 944, 974, 987, 1023, 1042, 1072, 1091, 1120