[ATH]

Originally Posted by CraigLo

The easiest way for me to fix this issue would be to use 12 SPRP tests which is sufficient to prove primality. Half the remaining numbers are prime after sieving so the code would take about 6-7 times longer to run.

It would be faster with 1 SPRP + 1 Lucas than 12 SPRP. At least the CPU code with the GMP library 1 Lucas test is about equal to 6.4-6.6 SPRP tests at 2⁶⁴ + 2*10¹⁶.
Why does 12 SPRP tests prove primality?