experimental-projects/oeis-research/Paolo P. Lava/Squarefree difference of semiprimes/group_trajectories.sf

#!/usr/bin/ruby

var table = Hash()

func f(n, k) {


    while (n.is_semiprime && n.is_squarefree) {
        var f = n.factor
        n = (f[1] - f[0])
        table{n} := [] << [k, f[1]]
    }
}


each_kv([6, 34, 82, 226, 687, 4786, 14367, 28738, 373763, 21408927, 158279834, 2690757467], {|k,v|
    say "#{k} = #{f(v,k)}"
    #assert_eq(k, eval(f(k)))
})

say table