521/Mistake

Source Work

1986: David Wells: Curious and Interesting Numbers:

The Dictionary

$2^{521} - 1$

1997: David Wells: Curious and Interesting Numbers (2nd ed.):

The Dictionary

$2^{521} - 1$

Mistake

In a few hours on the night of $30$ January $1952$, using the SWAC computer, Lehmer proved that $2^{521} - 1$ and the $183$-digit number $2^{607} - 1$ are both Mersenne primes.

This statement goes against the usual account that it was Raphael Mitchel Robinson who (by writing and running a computer program) accomplished this feat.

However, it is worth pointing out that the algorithm he implemented was designed by Derrick Henry Lehmer in the first place.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $2^{521} - 1$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $2^{521} - 1$