func ham_gen {
    var s = [[1], [1], [1]]
    var m = [2, 3, 5]
 
    func {
        var n = [s[0][0], s[1][0], s[2][0]].min
        { |i|
            s[i].shift if (s[i][0] == n)
            s[i].append(n * m[i])
        } << ^3
        return n
    }
}

var h = ham_gen()

var i = 20;
say i.of { h() }.join(' ')

{ h() } << (i+1 ..^ 1691)
say h()