A Sequence with a Mistake

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...

Sequence guru Neil Sloane on a sequence which puzzled him - until he spotted the mistake!

More Neil Sloane videos: http://bit.ly/Sloane_Numberphile

The OEIS: https://oeis.org

Hanny's Voorwerp: https://youtu.be/RDr6bSB6Vlg