The link to the proof for the fewest number of moves -- "(Try to work this out for yourself, or see the proof here.)" -- is not working. It leads to a page that says 'access denied.'

## Broken link?

The link to the proof for the fewest number of moves -- "(Try to work this out for yourself, or see the proof here.)" -- is not working. It leads to a page that says 'access denied.'