  We made the chaotic circuit proposed by Chua and the memristic circuit
proposed by Muthuswamy and Chua, and analyzed the behavior of the voltage of
the capacitor, electric current in the inductor and the voltage of the
memristor by adding an external sinusoidal oscillation ${\dot y}(t)\simeq {\dot
i_L}(t)$ of a type $\gamma\omega \cos\omega t$, while the ${\dot x}(t)\simeq
{\dot v_C}(t)$ is given by $y(t)/C$, and studied the Devil's staircase route to
chaos.
  We compared the frequency of the driving oscillation $f_s$ and the frequency
of the response $f_d$ in the window and assigned $W=f_s/f_d$ to each window.
When capacitor $C=1.0$, we observe stable attractors of Farey sequences
$\displaystyle W=\{\frac{1}{2}, \frac{2}{3},\frac{3}{4},\frac{4}{5}, \cdots
,\frac{14}{15},\frac{1}{1}\}$, which can be interpreted as hidden attractors,
while when $C=1.2$, we observe unstable attractors.
  Possible role of octonions in quantum mechanics and Cartan's supersymmetry is
discussed.
