A048409 Numbers whose consecutive digits differ by 7.
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 18, 29, 70, 81, 92, 181, 292, 707, 818, 929, 1818, 2929, 7070, 8181, 9292, 18181, 29292, 70707, 81818, 92929, 181818, 292929, 707070, 818181, 929292, 1818181, 2929292, 7070707, 8181818, 9292929, 18181818, 29292929
Offset: 0