The primes are already listed in OEIS but I think the searching range is not very deep there.

No more PRP's for $f(n)+1$ with $n \le 597$.

@TeresaLisbon My new project revealed no further prime numbers upto $n=600$. Did you also enter the numbers in factordb ?

I can create the program in no time, but it's the writing of the results and presenting them to you that might take some time.

← 3 messages moved from CURED

@MartinHopf That is depressing. Someone actually had this idea before :( The search limit is far better than mine. The numbers are very large already at this level.

I'm searching with PFGW at the moment, Maybe there is a small chance that we find a PRP for say $n \le 1000$.

How could you implement that there ?

I simply write the big numbers in a textfile with Pari/GP and then test them with PFGW. One Line per Number.

Ah, OK. And that works for such monsters ? I am impressed.

I created a routine to generate the products and copy it into factordb. This is another option.

I'm not sure how long a line in a textfile can be, but we will see.

$n = 1\ 000$ still worked.

Interesting, so factordb will do the PRP-test.

We only have to assign the numbers (not too many per hour). Upto $150$ k digits, they can be tested although this could take very long.

for n = 1000 for example both numbers are composite

for n = 999 both numbers are assigned

@MartinHopf Do you search both types simultaneously ?

No

$n=727$ now.

Not bad ! + or - ?

+1