A043929 Numbers n such that 4 and 5 occur juxtaposed in the base 7 representation of n but not of n+1.

33, 39, 82, 88, 131, 137, 180, 186, 229, 237, 279, 284, 327, 333, 376, 382, 425, 431, 474, 480, 523, 529, 572, 580, 622, 627, 670, 676, 719, 725, 768, 774, 817, 823, 866, 872, 915, 923, 965, 970, 1013, 1019, 1062, 1068, 1111