William D. JonesLooking for a specific integer sequence, but OEIS search is failing...
"Number of possible directed graphs with 'n' nodes"
I think it's 1, 6, and uhhh... I lost count after that.
I Can't Believe It's Not Zero!0 nodes: 1 graph
1 node: 1 or 2 graphs (do you allow a -> a?)
2 nodes: 3 graphs (disconnected, a->b, b->a)? or more (self-loops allowed)?
@steve No, these weren't DAGs, loops are allowed. I vaguely recall John McCall chiming in with the correct sequence. But that tweet is long gone (and based on location info, I was on my phone at the time, so I can't even look at my browser history).
I also remember that while calculating the number of graphs is easy, there's no "plug it in and immediately get an answer" formula for arbitrary 'n'. So for large 'n', you're f***ed :D.
@steve I have bad ADHD today, and I started thinking about the "number of possible FSMs with 'n' states" problem again. Also lamenting the fragile nature of hyperlinks.