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Old 2021-03-21, 14:22   #1011
garambois's Avatar
"Garambois Jean-Luc"
Oct 2011

7×97 Posts

Originally Posted by Happy5214 View Post
It was nowhere near quick enough. I rewrote the sigma calculation to use the well-known closed-form formula instead of a loop, and that significantly sped it up. The test you used (base 30 from 2 to 10k) now takes 2.2 seconds on my Kubuntu Focus. The new version is attached. I also found that s(30^(80640*3)) is in fact abundant, which is backed up by work I've posted on FactorDB.

Edit: The same range takes 6.3 seconds on my 2009-era Core 2 Quad desktop, which is a more similar comparison to your computer. I'd say that blows your script out of the water.

Many, many thanks !
8 seconds now for the program written in C against 55 seconds for the python program !
Congratulations !
So I'm going to stop my three python programs for bases 3, 5 and 7 and start your program in C.
I'm just going to add a hard drive backup of the exponents that generate abundant index 1 terms.

It is wonderful to all work together on this problem.
If we find what we are looking for for a base which is a prime number, we will have worked very well !

On your side, let me know if you manage to make the program even faster : this is what happened to me several times with my program in python !
But this time around, I think it's going to be very difficult to gain more speed ...

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