[Cryptography] Solving Matt's hash problem

[John Levine]

In Matt Levine's long article about cryptocurrencies, he describes in
accurate detail how hashing works, and mentions in an aside that he
cannot include the hash of the article in the article itself, you (the
reader) figure out why.

I know this is a preimage problem, but is there anything about making
the hash itself part of the input that would make it harder or easier
to solve?

R's,
John