Run every 5 minutes:
0 0/5 * 1/1 * ?
Run every 15 minutes, on the 5's (0:05, 0:20, 0:35, 0:50)
0 5/15 * 1/1 * ?
Run every hour at the top of the hour:
0 0 * * * ?
Run every hour at half past:
0 30 * * * ?
Run every 4 hours at top of the hour:
0 0 0/4 * * ?
