According to legend, a king promised to give the inventor of chess
any reward he asked for.
The inventor asked for one grain of rice on the first square,
doubling on each next square.
How much rice did he actually claim?

Question

Accepted Answer

About 18.4 quintillion grains — more rice than has ever existed. — 2^64 - 1. Exponential growth’s classic parable. The king went broke; the inventor made a point.

According to legend, a king promised to give the inventor of chess any reward he asked for. The inventor asked for one grain of rice on the first square, doubling on each next square. How much rice did he actually claim?