Definition:Ferrier's Prime
Definition
Ferrier's prime is the prime number:
- $\dfrac {2^{148} + 1} {17} = 20 \, 988 \, 936 \, 657 \, 440 \, 586 \,486 \, 151 \, 264 \, 256 \, 610 \, 222 \, 593 \, 863 \, 921$
Source of Name
This entry was named for Aimé Ferrier.
Historical Note
Ferrier's prime was discovered in $1951$ by Aimé Ferrier using a manual desk calculator.
It is generally considered to have been the highest known prime at the time, having $44$ digits.
However, it was eclipsed by $180 \times \paren {2^{127} - 1} + 1$ ($79$ digits), discovered in the same month by J.C.P. Miller and D.J. Wheeler of Cambridge University.
Exactly which was discovered first is debated, but Ferrier's is traditionally determined as being earlier.
Both were then well and truly superseded in $1952$, when Raphael Mitchel Robinson discovered the prime nature of $2^{521} - 1$ and a number of others.
Ferrier's prime is still the largest prime number to be discovered without the help of electronic computers, and this will probably remain the case.
Sources
- Weisstein, Eric W. "Ferrier's Prime." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/FerriersPrime.html