experimental-projects/factordb/batch_gcd_factor.sf

#!/usr/bin/ruby

# Factorize a list of numbers for FactorDB, using factors of pseudoprimes.

var nums = File(ARGV[0]).open_r.lines.map{.nums.last}.grep { defined(_) }.uniq

var gcds = Math.batch_gcd(
    [
        #nums...,
        glob(
            "../pseudoprimes/oeis-pseudoprimes/*.txt"
        )\
        .grep { File(_).size / 1024**2 < 10 }\      # keep only files that have less than 10MB
        .map{ File(_).open_r.lines.map{.nums.last}.grep { defined(_) && (.len\\0 > 25) } }.flat...
    ].uniq.sort...
).uniq.sort

for n in (nums) {
    var f = Math.gcd_factors(n, gcds).first(-1)
    f || next
    say "#{n} = #{f.join(' * ')}"
}