Question
Consider the following experiment :
Step 1. Flip a fair coin twice.
Step 2. If the outcomes are (TAILS, HEADS), then output Y and stop.
Step 3. If the outcomes are either (HEADS, HEADS) or (HEADS, TAILS), then output N and stop.
Step 4. If the outcoms are (TAILS, TAILS), then go to Step 1..
The probability that the output of the experiment is Y is 1k. Then k is