June 2021
 

[url]https://www.research.ibm.com/haifa/ponderthis/challenges/June2021.html[/url]

The second required property is completely meaningless as currently phrased. I assume it should say the numbers have to be at least 2.

What do you mean? That is the most important filtering criteria. Under a million, there are only about 40 numbers which suffice, and of them, less that a handful are prime.

[QUOTE=LaurV;579751]What do you mean? That is the most important filtering criteria. Under a million, there are only about 40 numbers which suffice, and of them, less that a handful are prime.[/QUOTE]

That's my opinion, too. I have only 246 under 2**64.

[QUOTE=uau;579736]The second required property is completely meaningless as currently phrased. I assume it should say the numbers have to be at least 2.[/QUOTE][QUOTE=LaurV;579751]What do you mean? That is the most important filtering criteria. Under a million, there are only about 40 numbers which suffice, and of them, less that a handful are prime.[/QUOTE]You are both correct.

The page has been edited to show "... > 1". Before it said "... ≥ 1"

[QUOTE=retina;579755]The page has been edited to show "... > 1". Before it said "... ≥ 1"[/QUOTE]
Oh...

Fun problem. Believe I got a correct answer.

Anybody go for the bonus *?

My bottleneck is primality proving.
I used YAFU implementation of APR-CL for solutions with less than 2k digits.

[QUOTE=swellman;581555]Fun problem. Believe I got a correct answer.

Anybody go for the bonus *?[/QUOTE]Apparently. The page with the challenge currently lists fifty-seven solvers who earned the bonus.

[QUOTE=swellman;581555]Fun problem. Believe I got a correct answer.

Anybody go for the bonus *?[/QUOTE]

Solved it today, largest solution I found so far is greater than 10^545

[QUOTE=Yusuf;581598]Solved it today, largest solution I found so far is greater than 10^545[/QUOTE]

10 ^ 545 good!
Go to the maximum yusuf.
we compare our max after the solution. if you want?