poem

don’t ask why it just came in my head

Quandary

So you have a fair coin that you found on the ground,
or at least that’s what everyone says.
But on each of N times that you’ve tossed it around,
you see every flip has been heads.

For which value of N should you start to suspect
that the coin isn’t actually fair?
For which values of N can you firmly declare
that the tails side is not even there?