Ten-talising primes

Number Theory Level 3

What is the largest value of $n$ in $10^n + 1$ if the equation resulted in a prime number?

1 solution

Robert Fritz
Mar 9, 2014

Search prime numbers on google.

As far as I know (several years out of date), this is an unsolved problem.

It is easy to show that if $10^n+1$ is prime, then $n$ must be a power of 2. But, it is not clear why $10^{2^k} + 1$ is not prime for larger $k$ .

Calvin Lin Staff - 7 years, 3 months ago

Could you please elaborate? Should induction be used? Is 2 right/wrong? Thanks in advance

Krishna Ar - 7 years, 2 months ago