Re: thanks to Don & Doppel....
Another option is if you learn a bit about programming, you can use a computer to figure this out experimentally, no math required (and less likely to make a mistake IMO).
This would be one of the easier programs you can write and an experienced programmer could do it in less than 10 minutes, I expect.
Although Don's solution of going to a web site is pretty quick too and it will give you the exact answer. :)