Erdős–Bacon numbers got their start when Simon Singh (reference 1 archived) was having lunch with me, and I observed that mine was 4. He writes for a living, so he wrote a column.

Oddly, I was long ago written out of this Wikipedia article.

There is a reasonable ambiguity about Erdős numbers, as people do publish posthumously with him, based on collaborations while he was alive.

There is also an ambiguity about Bacon numbers. One can take the spirit of the original dorm room bull sessions that started Bacon numbers, or one can take the idiosyncrasies as gospel of the web site that now reports Bacon numbers. For example, a mathematician can appear as themself in a documentary, and gain a Bacon number according to this web site. They defend this by observing that these mathematicians did experience film sets (so do caterers) but the reality is that it's too hard to clean the data. I've been interviewed multiple times for documentaries, and the experience bears no resemblance whatsoever to that of working on and acting in "A Beautiful Mind". The original intent was to count actors with credited speaking roles.