A044782 Numbers n such that string 6,9 occurs in the base 10 representation of n but not of n+1.

69, 169, 269, 369, 469, 569, 669, 699, 769, 869, 969, 1069, 1169, 1269, 1369, 1469, 1569, 1669, 1699, 1769, 1869, 1969, 2069, 2169, 2269, 2369, 2469, 2569, 2669, 2699, 2769, 2869, 2969, 3069, 3169, 3269, 3369, 3469, 3569