I’m posting this so I can refer to it later. The number being tested is n=(82065^19937 -1)/(82065-1). This is one part of a Miller-Rabin strong primality test. One checks that diff is -1, then one replaces the 32 on line 3 of the script by 16, and the value of res ought to be 1. Miller-Rabin strong primality test at Wikipedia: https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test . The OpenPFGW software, available for download: https://sourceforge.net/projects/openpfgw/
SCRIPT
DIM xx,(82065^19937 -1)/(82065-1)
DIM x2,((82065^19937 -1)/(82065-1)-1)/32
DIM base,3207170733475472351039832686350065599459652181714199927744788032412300337669571186035575395395662709
DIM res
DIM diff
POWMOD res,base,x2,xx
SET diff,res-xx
:PRINT base
:PRINT x2
PRINT xx
PRINT res
PRINT diff
