that depends on what your definition of "useless" is

0, 6, 16. The combination to my locker in seventh grade.

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597 . . . The Fibonacci series.

40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 63, 66, 69, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 126, 132, 138, 144, 152, 160, 168, 176, 184, 192, 200, 208. The numbers on the dial of a standard metronome.