perplexus.info :: Numbers : Is it, or is it not?

Home > Numbers

Is it, or is it not? (Posted on 2007-04-10)

Is (2⁵⁸+1)/5 an integer? A prime?

See The Solution Submitted by Federico Kereki

Rating: 3.6667 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re: solution --- easier nowadays

Comment 13 of 13 |

(In reply to solution by Charlie)

In the MATLAB command window:

>> digits 100

>> (vpa(2)^58+1)/5

ans =

57646075230342349.0

>> factor(ans)

ans =

[ 107367629, 536903681]

Posted by Charlie on 2020-11-23 07:15:36

Please log in:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info