A certain website has a counter which records the number of hits each day, and keeps a running total. The site gets between 10 and 20 hits, inclusive, per day.

The webmaster noticed that the running total was always prime.

What is the largest number of days the site could be up?
What is the largest number of days if the counter did not start from 1?

(In reply to some computer findings by Charlie)

I shouldn't have started with 2. But strike off the 2 and start with the 11, and there's a 23-day result.

Posted by Charlie on 2024-06-08 12:27:31