Two things:

1. I think the one way it might be profitable to enter the lottery with 13.9 million tickets might be on a sufficiently big rollover week. If the prize fund is only provided by you and your fellow competitors, then you and they will only get half or so back on average, but if there are some non-players beefing up the fund, ie those whose ticket money was nabbed last week and hung on to, it might work.

2. I had a fiddle with this calculation in Excel following Andy’s post. One thing confused me. I assume you got your data on prize fund etc from Wikipedia’s Lottery article: any idea why the percentages of the prize fund used for the various prizes don’t add up to 100? (2 10 16 52 = 80)