Full Moon + Friday the 13th = Rare Occurrence
October 13, 2000 is the last time a full moon landed on a Friday the 13th, and it’s not going to happen again until August 13, 2049.
The rare combination only happens very rarely because three independent factors need to come together: the moon phase (full), the day of the week (Friday), and the day of the month (13th).
The probability of all three happening on the same day is equal to multiplying each probability by each other.
The day itself is typically associated with bad luck instead of math, but nothing has been proven to back that belief.