- Figure out how to fix links in POD.
- Add advanced search syntaxes.
- In the OEIS::fetch Seq candidate, use X::OEIS::TooMany to determine
  when to increase the sample size for the search. Add a test for it.
- Can we use the `start` GET parameter to searches for seeking?
  Should that be supported?

- Offer downloading the whole 60 MiB archive of the OEIS and
  using it as a cache?
