Why Friday the 13th is a mathematical inevitability(scientificamerican.com)
scientificamerican.com
Why Friday the 13th is a mathematical inevitability
https://www.scientificamerican.com/article/why-friday-the-13th-is-a-mathematical-inevitability/
1 comments
Or 12 / 7 > 1 so most maybe all years will have a F13