The only mistake Satoshi Nakamoto made. Was to tell the world that the 1 million won't come back to the system. And we only have 20 million to work with. 
#bitcoin

https://m.primal.net/IsFs.jpg  

 Looks like Hal was just rounding for convenience. It's a Fermi estimate, so he's only looking for orders of magnitude. 

 Do you think it was a mistake or just accounting for 1M that he knew wouldn't move? 

 Meant that to be in response to the original note. 

 One of those rare moments when the answer precedes the question. It's like jeopardy 😄 

 Hahaha yes