A044557 Numbers n such that string 5,3 occurs in the base 7 representation of n but not of n+1.

38, 87, 136, 185, 234, 272, 283, 332, 381, 430, 479, 528, 577, 615, 626, 675, 724, 773, 822, 871, 920, 958, 969, 1018, 1067, 1116, 1165, 1214, 1263, 1301, 1312, 1361, 1410, 1459, 1508, 1557, 1606, 1644, 1655, 1704, 1753, 1802