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Old 2021-08-24, 20:45   #44
CraigLo
 
Mar 2021

1110112 Posts
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There is a list of base 2 pseudoprimes up to 264.
http://www.janfeitsma.nl/math/psp2/index

When you guys were doing the search up to 264 it would have been faster to do the Lucas test only if the number was a known 2-PSP.

Unfortunately the list only goes up to 264. Is there a fast way to generate the list of 2-PSP. When checking for gaps we need to do one Lucas test for every 1400 numbers. To check from 264 to 264 + 2.33 * 1016 (Gap=1552) would require 1.66*1013 Lucas tests. Can the list of 2-PSP be computed faster than this? We wouldn't even need to rerun what has already been done. We could just check for large gaps around the 2-PSPs.
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