2^n = 3 (mod n) : New solution: 10991007971508067

[Max Alekseyev]

> P.S. I am (still) finishing my exploration of all solutions below
> 10^16. That will bring at least a pair of two new terms to A050259. I
> also plan to extend my exploration to 1.1*10^16 later to cover the
> latest solution found by Joe.

Eventually I have finished exploration of all solutions below 10^16.
No new solutions found. That closes some initial gaps in A050259:

%S A050259 1,4700063497,3468371109448915,8365386194032363

Soon I will write a report on the details of my exploration. I also
started exploration of the interval [10^16,1.1*10^16] in order to
bring the latest Joe's solution into A050259.

Max