You misunderstand what he's saying. Because 60 doesn't divide into 7, don't use one 60 minute cron job. Use 7 cron jobs. You could get this magical 7 minute experience over a 24 hour period by creating the following 7 jobs:
0-56/7 0-21/7 * * * Command
3-59/7 1-22/7 * * * Command
6-55/7 2-23/7 * * * Command
2-58/7 3-17/7 * * * Command
5-54/7 4-18/7 * * * Command
1-57/7 5-19/7 * * * Command
4-53/7 6-20/7 * * * Command
Of course, the last job would finish at 23:55, and the next start at 00:00 which is bad. So you'd need to do it on a per day basis. Luckily there are 7 days in the week. So you would just need to write those 7 jobs above on a per day basis. You'd end up with 49 jobs all looking similar to this:
I wrote a simple script to generate cron tab specs for "every X minute", and while I enjoyed using gcd and lcm in a real application; something wasn't right. 7 is a very canonical and crazy case because it takes 7 days to cycle. but even then, it doesn't work with months except for February for non leap years.
