74 is cracked

Alex Bellos discusses how the Incans used knots in string (Quipu) to record numbers.Check out Brilliant (get 20% off their premium service): https://brillian...

A breakthrough by a Numberphile viewer (with help from some computers).

Extra footage: https://youtu.be/d6nUVa8EtlU

Original video: https://youtu.be/wymmCdLdPvM

See the paper by Sander Huisman: http://bit.ly/Sander_Paper

Discussed by Tim Browning from the University of Bristol.