experimental-projects/oeis-research/Daniel Suteu/Smallest base-n strong Fermat pseudoprime with n distinct prime factors/prog.sf

#!/usr/bin/ruby

# Smallest base-n strong Fermat pseudoprime with n distinct prime factors.

# See also:
#   https://oeis.org/A271874

func a(n) {
    return nil if (n < 2)

    var x = 1
    var y = 2*x

    loop {
        #say "Sieving range: #{[x,y]}"
        var arr = n.strong_fermat_psp(n,x,y)

        if (arr.len >= 1) {
            return arr[0]
        }

        x = y+1
        y = 2*x
    }
}

for n in (2..100) {
    say "a(#{n}) = #{a(n)}"
}

__END__
a(2) = 2047
a(3) = 8911
a(4) = 129921
a(5) = 381347461
a(6) = 333515107081
a(7) = 37388680793101
a(8) = 713808066913201
a(9) = 665242007427361
a(10) = 179042026797485691841
a(11) = 8915864307267517099501
a(12) = 331537694571170093744101