OK, n=56 is complete!
Estimate was 280214.
Final count after isprime() PARI checking script: 285415
2^n = 72057594037927936 so I used a kmax of 72060T.
Output:
n=56, kmin=0T, kmax=72060T, version=5.0, here T=10^12
Starting the sieve...
Using the first 11 primes to reduce the size of the sieve array
[285415 lines removed]
The sieving is complete.
Number of Prp tests=1503700301
Time=187990 sec.
So that's 2 days, 4 hours, 13 minutes, 10 seconds.
That's the end of it, not going to start n=57, there are too many of them!
