[seqfan] Re: A new and surprisingly hard elementary number theory question

Giovanni Resta g.resta at iit.cnr.it
Thu May 4 19:50:17 CEST 2017

Il 04/05/2017 16:48, Jack Brennen wrote:

> So it might be nice to know two things...  First, is 100,000,000 
> values of tau per CPU-minute a reasonable run rate?
It is difficult to answer since the rate changes greatly depending on 
the magnitude of
numbers and on the CPU.
My C program on a single thread on a i7-3930K (thats doing nothing else),
in  neighborhood of 10^12  runs at about  1500*10^6 tau/min,
and near 9*10^12  at about 800*10^6 tau/min.
Using multiple threads these numbers become 6000*10^6 tau/m and
and 3000*10^6 tau/m.

 > If so, where should one continue the search?

If my search for the similar sequence A075046 is correct, I've already
checked up to  10^13 (which is the limit of my program and also of my 


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