[vapemaster]

i always heard it called the birthday problem: https://en.wikipedia.org/wiki/Birthday_problem

[weirdly, someone discovered an birthday overlap today at work and i just re-google/wiki'd this today]

[bee_rider]

Huh, what are the odds that the same mathematical concept will come up in conversation twice on one day? We have invented the Synchronicity paradox, er, problem.

[ithkuil]

Baader–Meinhof phenomenon or frequency illusion.

Sadly nobody called it baader-meinhof paradox.