74 is cracked
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.