Comparative evolution of inner semimajor axis (top) and inner eccentricity (bottom left), with Fourier transform of inner eccentricity (bottom right) including position of peak frequencies (dotted lines), between N-body (black) and secular (purple) codes for two similar initial configurations: M₁ = 68.7 M_⊙, M₂ = 17.0 M_⊙, M₃ = 92.0 M_⊙, a_inner = 88.0 AU, a_outer = 6.82 kAU, e_outer = 0.670, i_mut = 78.3°.