inverse_znorder_generation.sf

#!/usr/bin/ruby

# Find all the integers d such that znorder(b, d) = n, for given integers (n,b).

# See also:
#   https://oeis.org/A226477
#   https://oeis.org/A345319

include("/home/swampyx/Other/Programare/experimental-projects/factordb/auto.sf")

func inverse_znorder(n, b=10) {
    divisors(b**n - 1).grep{.is_squarefree}.grep {|d| znorder(b, d) == n }
}

var base = 2

for n in (64..500) {
    inverse_znorder(n, base).each {|k|
       say k if (k > 2**64 && (kronecker(5, k) == -1) && k.is_composite && k.is_strong_psp(base))
    }
}