First we should look for life in this group. Let's begin with the prime numbers. 2, 3, 5, 7, 11, 13...

Chime in any time my spacey cousins.

Anyway, They're probably out there, but they're too busy surviving to call us for a nice chat.

I'm highly skeptical of alien visitation when we only just thought of the idea as we were about to enter space. Although possible, this is a fanciful idea that shows little in the way of critical thinking.

17, 19, 23, 29, 31, 37... anyone?

Well yes, alien visitation does seem a little far-fetched. After all, had we the technology to travel to other planets, what would we do? We'd mine it for its resources and set up an empire of sorts. Aliens havn't done this, and evolution should really dictate that the only intelligent surviving species would be those that thirst for power.
However, as electromanetic signals don't decay (however they do space out) They seti mission is perfectly plausible, especially as intelligent life would attempt to focus the electromagnetic waves they send.